Windows 10 Home PC 32 GB RAM but only 16 GB available to Windows (Dell Precision T7400, upgraded from Win 7 Home)

My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently from
4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home installed, and
I know that this has a 16 GB limit, so I wasn't too surprised to see in
Control Panel | System that it reported "32 GB RAM (16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher max
memory, I'm puzzled that Settings | System (and Control Panel | System)
still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is not
ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from the
BIOS config menu up to Control Panel | System. How do I enable Windows to
use the additional 16 GB of RAM?

NY wrote:
My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently
from 4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home
installed, and I know that this has a 16 GB limit, so I wasn't too
surprised to see in Control Panel | System that it reported "32 GB RAM
(16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher
max memory, I'm puzzled that Settings | System (and Control Panel |
System) still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is
not ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from
the BIOS config menu up to Control Panel | System. How do I enable
Windows to use the additional 16 GB of RAM?

The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory

In an administrator command prompt window, type this and check:

bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases

Paul

Paul wrote:
NY wrote:
My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it
recently from 4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7
Home installed, and I know that this has a 16 GB limit, so I wasn't
too surprised to see in Control Panel | System that it reported "32 GB
RAM (16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much
higher max memory, I'm puzzled that Settings | System (and Control
Panel | System) still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is
not ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right
from the BIOS config menu up to Control Panel | System. How do I
enable Windows to use the additional 16 GB of RAM?

The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory


In an administrator command prompt window, type this and check:

** bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

** bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases


** Paul

I upgraded from Win 7 Pro to Win 10 Pro without that problem.

"Paul" wrote in message
news
NY wrote:
My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently
from 4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home
installed, and I know that this has a 16 GB limit, so I wasn't too
surprised to see in Control Panel | System that it reported "32 GB RAM
(16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher
max memory, I'm puzzled that Settings | System (and Control Panel |
System) still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is
not ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from
the BIOS config menu up to Control Panel | System. How do I enable
Windows to use the additional 16 GB of RAM?

The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory

In an administrator command prompt window, type this and check:

bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases


Thanks for this. I forgot to say (but it's probably obvious) that it's 64
bit, not 32 bit.

I've run bcdedit but I'm not sure how to interpret the results:


Windows Boot Manager
--------------------
identifier {bootmgr}
device partition=C:
description Windows Boot Manager
locale en-US
inherit {globalsettings}
default {current}
resumeobject {5c85c246-e694-11e8-ba35-a13e094ed3ed}
displayorder {current}
toolsdisplayorder {memdiag}
timeout 30

Windows Boot Loader
-------------------
identifier {current}
device partition=C:
path \WINDOWS\system32\winload.exe
description Windows 10
locale en-US
inherit {bootloadersettings}
recoverysequence {dfb44823-e651-11e8-81a7-be8dede06390}
displaymessageoverride Recovery
recoveryenabled Yes
allowedinmemorysettings 0x15000075
osdevice partition=C:
systemroot \WINDOWS
resumeobject {5c85c246-e694-11e8-ba35-a13e094ed3ed}
nx OptIn
bootmenupolicy Standard

both "bcdedit" and "bcdedit /enum" give identical output.


I've seen elsewhere that CPU-Z should be run to list the memory. V1.86.0.x64
reports:

CPU: Intel Xeon E5420

Mainboard: Dell 0RW199
Chipset Intel 5400B
Southbridge 6321ESB
BIOS: Dell A01 1/31/08

Memory:
32 GB FB-DDR2
DRAM Freq 332.5 MHz
FSBRAM 1:1
CAS lat 5
RAS.CAS 5
RAS precharge 5
Cycle RAS 15
Bank cycle 20

SPD:
Slots 1-8 blank
Slots 9-12 FB-DDR2, PC2-5300 (333 MHz), Samsung
four different serial numbers, two different dates (2 are 08/09 and
2 are 26/09)

The memory was ordered as a 32 GB kit "for Dell T7400" (as described by the
vendor).


The PC has loads of slots, some on risers, but I installed the memory
according to Dell's instructions, doing a like-for-like replacement of the
original 4x 2 MB DIMMs that were supplied with the 4x 8 MB DIMMs that I
bought.


Any further suggestions?

In case it's relevant, the Control Panel | System screen shows that Windows
is activated, so it's not an unregistered version of Win 10 - it's inherited
the licensing of Win 7 Home Premium during the upgrade.

On 11/12/2018 7:33 AM, NY wrote:
My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently
from 4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home
installed, and I know that this has a 16 GB limit, so I wasn't too
surprised to see in Control Panel | System that it reported "32 GB RAM
(16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher
max memory, I'm puzzled that Settings | System (and Control Panel |
System) still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is
not ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from
the BIOS config menu up to Control Panel | System. How do I enable
Windows to use the additional 16 GB of RAM?

I'd say do an In-Place Repair Install. It'll keep your data, settings,
and installed apps in place. It'll just overwrite the existing copy of
Windows with itself like a factory reset.

Repair Install Windows 10 with an In-place Upgrade | Tutorials
https://www.tenforums.com/tutorials/...e-upgrade.html

Yousuf Khan

"Paul" wrote in message
news
The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory

In an administrator command prompt window, type this and check:

bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases

Also, Task Manager shows 16 GB of memory as "hardware reserved":

https://i.postimg.cc/7LPp71Yg/Untitled-1.png

"Yousuf Khan" wrote in message
...
On 11/12/2018 7:33 AM, NY wrote:
My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently
from 4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home
installed, and I know that this has a 16 GB limit, so I wasn't too
surprised to see in Control Panel | System that it reported "32 GB RAM
(16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher
max memory, I'm puzzled that Settings | System (and Control Panel |
System) still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is
not ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from
the BIOS config menu up to Control Panel | System. How do I enable
Windows to use the additional 16 GB of RAM?

I'd say do an In-Place Repair Install. It'll keep your data, settings, and
installed apps in place. It'll just overwrite the existing copy of Windows
with itself like a factory reset.

Repair Install Windows 10 with an In-place Upgrade | Tutorials
https://www.tenforums.com/tutorials/...e-upgrade.html

Having just finished upgrading from Win 7 Home Premium to Win 10 Home (a few
hours ago), is it likely that I then need to do an in-place repair install?
I don't want to do anything that's not essential (if it is, I'll do it!),
especially if it involves large downloads because my internet connection is
a miserly 1.7 Mbps - we started the upgrade/download process at about 17:00
last night and it took until about 11:00 today to get all the installation
and windows updates (it worked while we slept!!!).

It all became necessary because her Win 7 installation stopped installing
Windows updates and Windows software such as SQL Server, and nothing online
helped with resolving it (we tried a lot!). So she decided to bite the
bullet and upgrade to Win 10, which she'd been considering for a while,
since this would almost certainly clear the fault as a side-effect of the
upgrade. At first sight, the upgrade seems to have done a damn good job of
preserving user accounts, installed apps etc. About the only thing it didn't
do was preserve the UK-specific locale information such as date/time format,
but that was easily fixed, as was the dreaded "black-on-black" clock that
everyone has complained about - turning off small taskbar icons resolves
that for the clock and the running-application names in the taskbar.

NY wrote:
"Paul" wrote in message
news
The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory


In an administrator command prompt window, type this and check:

bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases


Also, Task Manager shows 16 GB of memory as "hardware reserved":

https://i.postimg.cc/7LPp71Yg/Untitled-1.png

OK, now we're getting somewhere.

FBDIMMs don't work, if there isn't continuity in the channel.
Seaburg talks to first DIMM. First DIMM talks to second DIMM
in channel. If first DIMM in channel is missing, second DIMM
"floats" and the OS accounting system calls it "hardware reserved".

https://www.hardwaresecrets.com/how-...memories-work/

https://www.anandtech.com/show/2059/4

Check out page 179.

https://downloads.dell.com/manuals/a...uide_en-us.pdf

"You must remove the memory riser cards from the computer in order to
install memory on them. The memory slots on each riser card are numbered
DIMM_1-DIMM_4. Memory must be installed on these cards in the order
that they are numbered; that is, DIMM_1 on riser card 1 must be populated
before DIMM_1 is populated on any other card. DIMM_1 must be populated
on each card before DIMM_2 can be populated on riser card 1, and so on.
Memory must be installed in sets of four with one of the four on each riser
card."

The memory controller ("Seaburg") has four channels.

https://ark.intel.com/products/34474...ory-Controller

There might be eight FBDIMM slots on the motherboard itself. This is
my numbering scheme, *not* the labels on the motherboard (which might
be different). My numbers here are purely to count slots. The
dashed lines indicate serial point-to-point buses.

5--1-- |Seaburg
6--2-- |Northbridge
7--3-- |Quad
8--4-- |channel

If I filled the slots like this:

x 1-- |Seaburg 16GB, 1/2 bandwidth
x 2-- |Northbridge
7 x |Quad #7 and #8 are "floating"
8 x |channel and cannot be read (user error)

then FBDIMMs 7 and 8 connect to SMBUS and their
SPD can be read, but the "data path" is floating,
so the BIOS probe can't touch them. Neither can
the OS use them.

I won't give feedback on the usage of risers, unless
you find risers are present. It's the same idea, but
it will take me more drawings to illustrate what
to do. When the risers are plugged into 1,2,3,4 in
the above diagram, 5,6,7,8 FBDIMM slots on the motherboard
cannot be used (crash-ola if you do use them).

Paul

On 11/12/2018 9:20 AM, NY wrote:
Having just finished upgrading from Win 7 Home Premium to Win 10 Home (a
few hours ago), is it likely that I then need to do an in-place repair
install? I don't want to do anything that's not essential (if it is,
I'll do it!), especially if it involves large downloads because my
internet connection is a miserly 1.7 Mbps - we started the
upgrade/download process at about 17:00 last night and it took until
about 11:00 today to get all the installation and windows updates (it
worked while we slept!!!).

Oh, I see, I just noticed that you mentioned that you had Win 7 Home
installed previously but now have Win 10 Home. I was previously under
the impression that you had gone from an earlier version of Win 10 Home
to Win 10 Home (version 1803).

Okay, then the question would be did you install the additional RAM
before or after the upgrade from Win 7 to Win 10? Perhaps try removing
the additional RAM, boot into Win 10, shutdown, and then reinstall the
RAM, and reboot? You may still need to do the In-Place Repair, to get
rid of any leftover config files that maybe trying to limit your RAM.

It all became necessary because her Win 7 installation stopped
installing Windows updates and Windows software such as SQL Server, and
nothing online helped with resolving it (we tried a lot!). So she
decided to bite the bullet and upgrade to Win 10, which she'd been
considering for a while, since this would almost certainly clear the
fault as a side-effect of the upgrade. At first sight, the upgrade seems
to have done a damn good job of preserving user accounts, installed apps
etc. About the only thing it didn't do was preserve the UK-specific
locale information such as date/time format, but that was easily fixed,
as was the dreaded "black-on-black" clock that everyone has complained
about - turning off small taskbar icons resolves that for the clock and
the running-application names in the taskbar.

Yeah, I don't know that the Win 7 problem might have been either. But it
was a good idea to upgrade to 10 nonetheless. There is no general
support for Win 7 anymore, just extended support for corporations.

Yousuf Khan

On 11/12/2018 8:09 AM, Weatherman wrote:
I upgraded from Win 7 Pro to Win 10 Pro without that problem.

Both Win 7 Pro and Win 10 Pro have much higher limits than the Home
versions of those OS. In Win 7 Home Basic, the limit was 8 GB, that was
increased to 16 GB for Home Premium, and 192 GB for everything above that.

Win 8/8.1 basic had a limit of 128 GB, and 512 GB for everything above that.

Win 10 Home also has a limit of 128 GB, like Win 8 basic, while the
upper limit has been extended to 2 TB for everything above that.

Yousuf Khan

"KenW" wrote in message
...
On Mon, 12 Nov 2018 12:33:16 -0000, "NY" wrote:

My wife's Dell Precision T7400 PC has 32 GB RAM (I upgraded it recently
from
4x2GB DIMMs to 4x8GB DIMMs). It originally had Windows 7 Home installed,
and
I know that this has a 16 GB limit, so I wasn't too surprised to see in
Control Panel | System that it reported "32 GB RAM (16 GB available)".

Having just upgraded it to Windows 10 Home 1803 which has a much higher
max
memory, I'm puzzled that Settings | System (and Control Panel | System)
still reports "32 GB, 16 GB available".

I've check MS Config | Boot | Advanced and the "Maximum Memory" box is not
ticked to enforce a lower limit.

What am I doing wrong? The PC clearly sees that it has 32 GB, right from
the
BIOS config menu up to Control Panel | System. How do I enable Windows to
use the additional 16 GB of RAM?

Windows update may not have read your installation correctly. I would
download the upgrade using the Media Creation Tool and try a repair
install. Run the SETUP.exe file from within Windows 10. DO NOT BOOT
from the dvd/flash stick.

I was hoping that wouldn't be necessary, since my internet connection is
only 1.7 Mbps so it will take ages. Still, if that's what it needs, that's
what I must do :-)

Will the repair installation be an in-place upgrade, preserving all the
installed applications and user accounts, or will it be necessary to wipe
the user accounts and installed apps? Just so I know what to expect.

It's an upgrade from Win 7, so I have a Win 7 licence key. Is that what it
will ask for when I do the repair installation? Oddly I wasn't asked for
this when doing the original upgrade yesterday.

"Paul" wrote in message
news
Also, Task Manager shows 16 GB of memory as "hardware reserved":

https://i.postimg.cc/7LPp71Yg/Untitled-1.png

OK, now we're getting somewhere.

FBDIMMs don't work, if there isn't continuity in the channel.
Seaburg talks to first DIMM. First DIMM talks to second DIMM
in channel. If first DIMM in channel is missing, second DIMM
"floats" and the OS accounting system calls it "hardware reserved".

https://www.hardwaresecrets.com/how-...memories-work/

https://www.anandtech.com/show/2059/4

Check out page 179.

https://downloads.dell.com/manuals/a...uide_en-us.pdf

"You must remove the memory riser cards from the computer in order to
install memory on them. The memory slots on each riser card are
numbered
DIMM_1-DIMM_4. Memory must be installed on these cards in the order
that they are numbered; that is, DIMM_1 on riser card 1 must be
populated
before DIMM_1 is populated on any other card. DIMM_1 must be populated
on each card before DIMM_2 can be populated on riser card 1, and so on.
Memory must be installed in sets of four with one of the four on each
riser
card."

Thanks for that. I had actually found that document and researched it when I
originally upgraded the PC from 8 GB (4x 2 GB) to 32 GB (4x 8 GB) a few
months ago - and *then* discovered the built-in 16 GB limit of Windows 7
Home ;-)

But I thought once I upgraded to Win 10, that limit would go away
spontaneously.

I had the same idea as Yousuf: temporarily removing half the RAM, letting
the BIOS adjust to 16 GB and letting Windows discover this amount of memory,
and then adding the memory again. I did that a few minutes ago, and hit the
restriction that the PC will not boot, even to the BIOS screen, unless 4
DIMMs (or multiples of 4, presumably) are present. Grrr. I wonder where I
put the old DIMMs - I could put two of those in place of 2 8 GB ones and go
through the process that Yousuf describes. performance with mis-matched
DIMMs may be reduced, but it should at least boot.

I removed the two DIMMs from slot 1 of the riser cards 3 and 4, leaving just
the two in slot 1 of risers 1 and 2, so I complied with the first part of
the Dell instructions... but not that killer final sentence ;-)

If I find the old DIMMs, I'll give it a try and report back. I really
*don't* want to have to do anything that will upset a PC that seems to work
perfectly in Win 10 (installed apps seem to work), so that's why I'm being
hesitant about another installation/repair of Windows - if it works, don't
disturb it... But if all else fails, maybe I'll have to hope that a repair
from the Media Creation Tool will leave everything else untouched, or else
accept that if it doesn't, it's time to get out all the installation CDs etc
and do an inventory of what's installed, what browser passwords are
pre-saved (and then forgotten about) - and obviously save all user files off
the C drive in case of disasters. Which reminds me, I haven't backed up my
wife's PC for ages. I do mine most days, depending on what changes, but I
tend to neglect hers, partly because she's only just started using it again,
after needing a more powerful PC than her laptop for a new course that she'd
studying.

NY wrote:

Memory:
32 GB FB-DDR2

SPD:
Slots 1-8 blank
Slots 9-12 FB-DDR2, PC2-5300 (333 MHz), Samsung

The memory was ordered as a 32 GB kit "for Dell T7400" (as described by the
vendor).

The PC has loads of slots, some on risers, but I installed the memory
according to Dell's instructions, doing a like-for-like replacement of the
original 4x 2 MB DIMMs that were supplied with the 4x 8 MB DIMMs that I
bought. | |
| |
GB, not MB -----'-----------------------------------------'

Why are any of the memory modules on risers?

There are 8 memory slots. You only have 4 memory modules. Why were
they plugged into the 2nd bank instead of the first?

https://downloads.dell.com/manuals/a...uide_en-us.pdf

From the online manual, the risers are only needed if you want to use 16
memory modules (above the 8 provided as memory slots on the mobo).

The manual also states the modules sizes allowed in the slots are 512MB,
1GB, 2GB, and 4GB. 8GB is not mentioned. If the slots don't have
sufficient address lines to access the higher memory capacity then you
can't use the higher capacity memory modules.

You get the 32GB maximum memory capacity (without risers) by using 8x4GB
memory modules, not by putting in 4x8GB modules. You can get up to 64GB
memory by using the risers (16x4GB) but you are still limited to 4GB
modules.

According to the manual, the memory risers are numbered, and its number
must match the memory slot number. Only 4 risers can be used and only
in the white memory slots. If risers are used, slots 5-8 on the mobo
must be left vacant. Each riser can hold 4 memory modules, so a total
of 16 memory modules (4x4) if the risers are used for a total of 64 GB
of memory using the 4 GB maximum size for each memory module.

Also, on a riser card, you cannot populate a slot before the same slot
has been populated on another riser. That is, you must populate DIMM1
on riser1 and not populate any of its other slots until you have
populated DIMM1 in the other risers. So, by using the risers, your 4
memory modules would all have to be in the DIMM1 slot of 4 risers. When
a slot on a riser is populated, the same slot on the other risers must
also be populated; i.e., you must install in sets of 4 to populate the
same DIMM1 slot in each of the 4 risers. However, the specs still say
the maximum module size is 4 GB, not 8 GB.

To achieve a 32 GB capacity in memory, seems you could've used 8x4GB
memory modules just in the 8 memory slots on the mobo, or 8x4GB in the
risers with DIMM1 and DIMM2 populated in each of the 4 risers that must
be used as a set.

There 8 memory slots on the mobo. With the 4 GB max size per memory
module, that gives you 32 GB of total memory. You don't get to put in 8
8 GB modules for 64 GB with the onboard slots. Similarly, with the
risers, you get to use 16x4 GB memory modules for 64 GB total memory,
not with 16x8 GB memory modules (for 128 GB total). Whether you use
the onboard slots or the risers in them, you are still limited to 4 GB
memory modules.

Just WHO is/was the "vendor" where you bought this 32GB kit that stated
it was for your computer model? Did the vendor specifically state that
their "kit" was for your model? They should've sold you eight 4GB
modules, not four 8GB modules. Or did you assume you could double the
memory module size and buy a 4-count package of DIMMs (i.e., the vendor
never stated their package was for your specific model)?

I'm going by the Dell manual that I found for a T7400 model. Maybe
there are different model versions that have different memory capacity
and support larger memory modules. The manual that I found (Dell sucks
for finding support on long discontinued models - I had to use a search
engine outside of dell.com to find the manual at dell.com) says 4 GB is
the max size for memory modules and that's whether you use the onboard
slots or the risers to effectively double the slots (not double the
memory module size).

When I went to amazon.com and searched on "dell precision T7400 memory",
all the vendors there were selling memory kits that used 4 GB memory
modules, or smaller. None were selling kits with DIMMs over 4 GB. I
did find Dell's spec sheet on the T7400 at:

https://www.dell.com/downloads/globa..._specsheet.pdf

That says max memory (with the risers) is 128 GB, not the 64 GB max
noted in the manual. Could be Dell came out with a later version of the
same model that added another address line to double the maximum memory
capacity. Even if memory modules are not yet available at a higher
capacity when the manual is published, the manual shouldn't be saying
the max memory module size is 4 GB if the hardware supports 8 GB
modules. Reviews or 3rd party specs published at the time the T7400 was
first released note a 64 GB max memory capacity, not 128 GB.

The SPD info that CPU-z and other similar tools will read from the
memory modules does not reflect what the hardware can support.

NY wrote:

"Paul" wrote in message
news
The BCD can limit memory.

https://docs.microsoft.com/en-us/win...ipulate-memory

In an administrator command prompt window, type this and check:

bcdedit

Usually, something like this isn't needed. This dumps "noise"
in the file.

bcdedit /enum

I would have thought MSConfig would be doing the same thing.
But maybe it's intended for boot.ini instead ?

The memory license for Win10 Home is 128GB, Win10 Pro is 2TB
(enough for an Epyc). You're right, that this should not be
happening - but what could be happening is the BCD values
were preserved on the upgrade install.

https://docs.microsoft.com/en-us/win...ndows-releases

Also, Task Manager shows 16 GB of memory as "hardware reserved":

https://i.postimg.cc/7LPp71Yg/Untitled-1.png

Perhaps from an unsupported hardware configuration. The Dell manual
that I found on the T7400 (noted with its URL in my prior reply) says
that the maximum memory capacity is 64GB (when using the risers), 32GB
without, which not the 128GB mentioned in Dell's spec sheet. Dell's
manual and their spec sheet don't match on what is the maximum memory
capacity and maximum memory module size. The manual lists up to a 4GB
max size per memory module, not the 8GB sticks you bought.

I've also run across low- versus high-density memory modules. Many
mobos and their BIOSes can only handle low-density memory modules. The
chipset on the mobo may not handle the memory architecture of
high-density memory modules. Even if your mobo's chipset can handle
high-density memory modules, don't mix low- and high-density modules in
your configuration. Back for computers as old as yours, high-density
modules had low compatibility with computers. Even if the seller
qualified his auction or product with a notice it was a high-density
module, users didn't know what that meant and were only looking at the
module's capacity. The low-cost high-density modules had low
compatibility. As I recall, the high-density modules had memory chips
on only one side of the PCB versus the low-density modules that have
memory chips on both sides. Back then, you couldn't give away high-
density memory to the educated users but you could sell it cheaply to
the typical user. They might have a disclaimer or tech details
somewhere to prevent buyers from returning the unusable memory.
High-density memory modules in a mobo whose chipset cannot support that
memory addressing architecture could only access half of the rated total
capacity of the module. The high-density memory modules appeared long
before the mobo chipset could support them. I'm not sure when Dell came
out with their Precision T7400. From some articles, maybe it showed up
around 2012. I don't remember when was the debacle of high-density
memory modules appearing before chipsets would support them, only that I
had to watch for this scam for my prior PC.

https://www.techrepublic.com/blog/us...-requirements/

I did find:

https://www.dell.com/support/home/us...driverid=kv78g

for a BIOS update dated back in 2012. Don't know what BIOS version you
have. I found that by using a search engine instead of hunting around
Dell's web site for BIOS updates. I happened upon:

https://www.dell.com/support/home/us...t7400/diagnose

I had to wait a l-o-n-g time for them to update their page. When it did
paint, I see the latest BIOS version is A11 (released 2012-06-28). If
you update the BIOS, also get their chipset driver package since it may
be needed by the OS to handle the memory through the BIOS that you
added.

Another possibility is you have hardware configured to suck up some of
the system memory. Are you using a video daughtercard or onboard video?
Onboard video requires it consume a portion of the system memory. It's
general slower than VRAM but cheaper, so the onboard video is configured
in the BIOS to steal away some of the system RAM. Check your BIOS
settings to see how much is allocated to the onboard video. Maybe it's
a percentage instead of a fixed amount. BIOS settings won't change
because you changed to a different OS. Other devices can be configured
in the BIOS to reserve system memory. That's an old mobo, so it has AGP
settings in its BIOS. Any memory reserved for AGP won't be available to
the OS. It should not have a 16 GB size choice but all those devices
that are allocated reserved memory in BIOS will add up.

Another possibility is the memory remapping function in the BIOS is not
enabled. It can be called memory remapping, memory extension, or
something similar. Some BIOSes are extremely basic (designed for boobs)
but some have tons of settings. You might just want to reset the BIOS
to an optimal or standard config and then revisit its individual
settings to see if you want to customize differently.

Run msconfig.exe, the Boot tab, click on Advanced Options button, and
check if the "Maximum memory" option is enabled. Don't see why you
would've enabled this before. Both the "Number of processors" and
"Maximum memory" optionsshould be unchecked. If you change these
values, you have to reboot to effect those changes.

What is reported and testable when you boot using memtest86
(https://www.memtest86.com/)?

Sometimes a BIOS update allows accessing more system RAM. The hardware
that is provided in a setup may outstrip what the old BIOS version will
support. That is, a newer BIOS is sometimes needed to unlock all the
hardware functionality (well, more of it). With that being an old
discontinued model, finding a BIOS update from Dell might be difficult.
You might have to call them to report your BIOS version (it's shown in
the POST screen) and ask if a later version is available for that model
(be sure to get the model number off the mobo, not for the entire
computer).

Um, you did check that each memory module was FULLY seated in its slot
(whether onboard or in a riser) and the risers (if used) were fully
seated, too ... right?

"VanguardLH" wrote in message
...
Why are any of the memory modules on risers?

There are 8 memory slots. You only have 4 memory modules. Why were
they plugged into the 2nd bank instead of the first?

I'm not sure. The 4 GB (not 8 GB - I was wrong) that it came with was fitted
by Dell as 4x 1 GB DIMMs on two riser cards. Maybe because it's easier to
remove those risers and fit DIMMs to them than it is to fit the DIMMs
directly to the motherboard when the sockets are at the bottom of a deep
"well" bounded by the walls of the cage that supports risers (if any) and
the walls of the case.

Anyway, I bought the new DIMMs (and the vendor offered 8 GB DIMMs as the
largest size; I hadn't noticed the max 4 GB DIMM in the Dell manual) and
fitted them exactly like-for-like in the risers. At the time I chose to
remove the 4 GB of 1 GB DIMMs, but I've since fitted them in addition.


Anyway, I've solved the problem of Windows reporting (on Control Panel |
System) "Memory 32 GB (16 GB usable)". It's all down to turning on
virtualization in the BIOS!

I started to suspect something when I temporarily replaced the 32 GB with 4
GB as Yousuf suggested, prior to booting like that, shutting down and then
replacing the 32 and letting Windows discover it. With 4 GB, Control Panel |
System reported "4 GB (2 GB usable)". So I was now well below any limit of
16 GB that might have been inherited from Windows 7 64 Home Premium... and
yet it was still reporting that only half the memory was usable. As an
aside, Windows 10 with 4 GB of RAM moves like a wounded snail - it is
painfully SLOW :-)

My wife did some Googling (it's OK as long as you do it in private!) and
discovered many forum postings about Windows 10 reporting "n GB (n/2 GB
usable)" for any value of n.

The two things that were suggested we

- make various BIOS changes, amongst which was to turn on Virtualization
(the rest didn't apply to my BIOS)

- change the page file strategy from "Allow Windows to manage swap file for
all drives" and "System managed sized" to turn off "Allow..." and set
hard-coded minimum of n*1.5 and maximum of n*4, when n is the amount of RAM

The second (which I tried even while I had 4 GB RAM) made no difference to
Control Panel | System and Task Manager | Memory, but turning on
Virtualization is the single thing which instantly made all 4 GB usable.

After that success I decided to be bold and I added the new 8 GB DIMMs as
well (putting the 8s in Slot 1 on each of the four riser banks and the 1s in
Slot 2), to give a total of 36 GB. What would PCs of the 1990s have made of
36 GB RAM, at a time when a few MB was luxury and with DOS you had to juggle
with HIMEM and Upper Memory (been there, done that - trying to work out the
order to load different network stacks to make best use of memory under 1
MB).

And the PC came up and reported 36 MB (and all of it usable/available to
Windows).

I'm not sure what the best advice is on page file strategy - hard-coded
versus letting Windows manage it. Any comments, anyone? Should I reset it
back to the default of "Allow..." and System Managed size?



To sum up: the "16 GB available" was not a carry-over from Windows 7 that
had been on the PC before. It was an inherent restriction that seems to
affect Windows 10 (at least on this PC), that half the memory (no matter how
much you have) seems to be "hidden" from Windows unless virtualization is
turned on in the BIOS.

My wife is over the moon to have 36 GB. Not because she needs it but because
she had bought it at great expense (the vendor charged almost the same for
2, 4 or 8 GB DIMMs so she got the biggest) and wanted to be able to make
full use of them if she ever needed to run a memory-hungry app.