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

On 12/11/2018 12:33, NY wrote:


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".



It could be that you have installed incompatible modules. Did you not
bother to scan your machine BEFORE purchasing them? Crucial have a free
scanner and you could have used it before buying anything. The scanner
tells you what is the capacity on your machine and which brand is
compatible with what you already have.

Well, treat this as a lesson learned. Next time do a through research
before taking out your credit card and using it just because you like
spending time on the net.

Why does your wife need all that RAM? Is she cleverer than you?




--
With over 950 million devices now running Windows 10, customer
satisfaction is higher than any previous version of windows.

NY wrote:


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.

You should be testing with memtest, and do at least
one full pass. (There's a pass counter on the 640x480 screen.)

http://memtest.org/

Downloads are half way down the web page.

Various media formats are available, to suit
machines with fewer storage options.

I recommend memory testing, on average, about once
a year, as part of preventive maintenance.

That's not the only test you can run, but it does
do a stuck-at test for you. Memory failures come in
a couple types. Stuck-at faults are memory bits
that can no longer be flipped. Transient faults
(never the same address, twice) can be cause by
bus noise issues. The FBDIMM isn't likely to have
bus noise issues, but you can still have stuck bits
on the memory chips themselves.

Memtest also has a bandwidth display, which you can
check to see if the value makes sense or not. For
example, my quad channel system here, the measured
bandwidth is only 25% of theoretical, which means
the thing basically runs dual channel mode inside.
Not a big deal, except in bar bets.

Paul

NY wrote:

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?

In the past, I set max and min pagefile size to the same 1.5*N value
(where N is my physical system RAM). Having the same size for min and
max meant the pagefile stayed the same size hence preventing further
fragmentation of that file (after doing a defrag of it). Later with an
8GB system, it seemed ridiculous to have 12GB of fixed space allocated
to a pagefile when there was 8GB of real RAM available. I knew that a
zero-sized pagefile was incorrect because Windows wants some, some
programs will error or fail if they request some but none is available,
and some games error, fail to load, or crash without some (they want to
offload their textures and objects into the pagefile which is on the
disk because access is faster than doing file I/O on the disk). So I
reduced the pagefile down to 4GB which seemed more than large enough.
After a couple years and some updates to Windows and the programs, I
started getting 7A BSODs at infrequent intervals. I did chkdsk /r,
memtest, and a slew of other testing but nothing pointed at defective
hardware and all testing was okay. I noticed the BSODs were after using
Macrium Reflect free to perform a scheduled backup. The backup job
completed okay and even the following verification of the backup. It
was 5 minutes after the backup completed that a BSOD happened.

I had also split the pagefile across 2 drives. If Windows sees part of
the pagefile on a drive other than the one for the OS, it's supposed to
get preference to using that other pagefile space. Now all the pagefile
space is on the SSD. No splitting across drives and different types of
drives (SSD for OS drive, HDD for data drive). I changed to system
managed instead of trying to prevent fragmentation of the file with
varying size (which different min-max values might do and system-managed
would do) because fragmentation on an SSD doesn't cause the slowdown as
it does for seeks on an HDD (the SSD still needs to get optimized
occasionally to reduce fragments to reduce the meta data from all of
them which could exceed the handling supported in the file table and why
in Task Scheduler you'll find a scheduled defrag using MS's tool - so I
reenabled that scheduled event). Although it says 12GB is reserved,
that doesn't mean used. Windows, when pagefile is system managed, will
vary the size of the pagefile as needed. When min is less than max,
them is physically allocated on the drive but the remainder up to the
max is only reserved for if and when it is needed.

I had replaced an HDD with an SSD (and moved the old HDD to a data-only
drive but with some pagefile space). To troubleshoot the BSODs, I moved
all of the pagefile space to the SSD (the OS drive). With the changes
in the pagefile (not split across different types of drives, well, not
split at all and only on the OS drive, and using system managed sizing),
I'll have to wait a month, or two, to see if the BSODs still occur 5
minutes after the backup & verify completes (which go to a different HDD
but that's been chkdsk /r'd and tested, too).

While my SSD is a lot smaller than my HDDs (256GB versus 1TB and 2TB), I
was trying to save space by moving most of the pagefile off the SSD.
That would also reduce the number of writes to the SSD since there is a
max number of writes the SSD can handle. I'd rather have a stable PC
than worry about more writes reducing the lifespan of the SSD. I have
scheduled backups (daily-differential and weekly-full to the internal
HDD, copied to a USB-attached HDD, and monthly-full to USB flash drives)
to recover from hardware failure. I had originally split the pagefile
because file I/O to the pagefile was parallel to writes to the OS drive,
so paging would be faster. That wasn't true anymore when using the SSD
where the other-drive pagefile would now be a lot slow than the part of
the pagefile on the SSD. I had fixed the pagefile size to eliminate its
fragmentation but that's not an issue when using an SSD.

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.

Most of the articles that I found on "hardware reserved" for memory
pointed back to the BIOS. A new BIOS version was needed (so it matched
the better capable hardware), devices had been allocated space (e.g.,
onboard video), and other settings that would reserve some memory making
it unavailable to any OS. I had not thought that lack of virtualization
support would cause allocation of memory the OS could not reach.
Because BIOS had been mentioned often, in another reply I had suggested
resetting the BIOS to either its default or optimized config. In my
mind, the Xeon was an old processor, so I didn't think it supported VT-x
virtualization. I haven't dealt with Xeon PCs for a very long time.
https://en.wikipedia.org/wiki/List_o...icroprocessors shows
the CoffeeLake family was released this year.

https://www.intel.com/content/www/us...rocessors.html

I looked up one of the Xeons (probably not yours) and it does list VT-x
as supported. Since VT-x virtualization is supported by the Xeon
processor, seems peculiar that it was disabled in the BIOS. You might
want to reset the BIOS settings. After a reset, check the VT-x option
is enabled (along with other BIOS settings, like AGP aperture size).

You might also consider replacing the CMOS battery. Rarely are the BIOS
settings read directly from the EEPROM chips where the BIOS settings are
stored. Instead during boot the settings are read from the CMOS table
where a copy of the BIOS settings are stored. If the battery goes weak
or dead, the CMOS table can get corrupted. If the CMOS battery is over
5 years old, replace it.

I noticed Device Manager (devmgmt.msc) can let you see what memory
ranges have been reserved for hardware (in the BIOS). Load devmgmt.msc
and go to the View - Resources by connection menu and expand the Memory
node in the tree list. I haven't bothered to figure out which reserved
memory ranges are included in the hardware reserved range. Maybe they
all are. Some info he

https://blogs.technet.microsoft.com/...ysical-memory/

NY wrote:

I hadn't noticed the max 4 GB DIMM in the Dell manual

Though it's not unusual for limits that apply when a product is new (and
are noted in the manual) to be altered over the years by firmware upgrades.

"?? Good Guy ??" wrote in message
news On 12/11/2018 12:33, NY wrote:

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".


It could be that you have installed incompatible modules. Did you not
bother to scan your machine BEFORE purchasing them? Crucial have a free
scanner and you could have used it before buying anything. The scanner
tells you what is the capacity on your machine and which brand is
compatible with what you already have.

Well, treat this as a lesson learned. Next time do a through research
before taking out your credit card and using it just because you like
spending time on the net.


Actually I *did* run the Crucial scanner on the PC. Crucial is the first
place I go to for memory, just like Google is the first place for searching
the web. Unfortunately they didn't sell any that was compatible with the
PC - it's fairly old DDR2 memory. I had to try a smaller company which was
the only one that advertised that type of memory for that particular model;
I made sure they had a "guaranteed to work with this PC" clause so I could
return it if there was a problem.

The initial intention was to replace the existing RAM with new RAM, so I was
looking for RAM DIMMs that would work with the PC but not necessarily with
the existing DIMMs. It's only very recently that I've tried the two
together - long after experiencing the original "32 GB (16 GB available)"
problem.

OK, Dell's original manual for the PC only lists DIMMs as large as 4 GB, and
I bought 8 GB ones. I admit that I hadn't seen that restriction and that I
was lucky the larger ones did work, though again it would be covered by the
vendor's compatibility guarantee. I *did* do my research to the extent that
I knew DIMMs needed to be added in groups of 4 with this motherboard.


Anyway, the problem was not one of compatibility. It was due to a BIOS
setting that needed to changed and which caused *any* amount of memory
(whether 4 GB, 32 GB or 32+4=36 GB) to report 50% not being available to
Windows 10: when I put the original 4 GB back temporarily, Win 10's Control
Panel | System reported "4 GB (2GB available)"; it had not done this before
the OS upgrade when I still had Win 7.

Andy Burns wrote:
NY wrote:

I hadn't noticed the max 4 GB DIMM in the Dell manual

Though it's not unusual for limits that apply when a product is new (and
are noted in the manual) to be altered over the years by firmware upgrades.

In this case, it's hardly the normal constraints, because
it's an FBDIMM interface. The AMB deals with the vagaries
of the DRAM chip behind it (make a new AMB if different
DRAM come along). The Northbridge on the motherboard,
only has to feed the AMB an address. And whoever invented
the FBDIMM interface, can select a sufficiently elevated
size so that the package is more future proof. There really
isn't a good excuse for a size limit, until they have to
transmit an extra byte on the bus to carry it.

Paul

Andy Burns wrote:

NY wrote:

I hadn't noticed the max 4 GB DIMM in the Dell manual

Though it's not unusual for limits that apply when a product is new (and
are noted in the manual) to be altered over the years by firmware upgrades.

That's why I mentioned Dell's data sheet and other reviews noting twice
the maximum system RAM capacity might've been due to a BIOS update.
From what I saw at Dell's site (which required using a search engine
instead of Dell's search) was the latest BIOS version is A11 dated back
in 2012. The hardware may outstrip the functions within a BIOS until a
later update. The OP should look at the POST screen to see what he has.
I would only do a BIOS update if I had a the computer on a UPS for a
desktop or a fully charged battery for a laptop and make sure to first
copy the old BIOS to archive in case the new BIOS has problems; however,
a screwed up BIOS update can render the computer unusable resulting in
not being able to burn in the old BIOS .bin file.

However, the OP got all of his system RAM available by changing a BIOS
setting: enabling the VT-x virtualization option. His Xeon processor
probably supports the virtualization feature (the latest ones do but I
don't know about his), so the question is why it got disabled requiring
him to reenable it. His PC is probably over 5 years old and should have
its CMOS battery replaced. For pre-builts, I usually schedule to
replace the battery after 3 years because I won't know how old is the
battery inside the pre-built or when the pre-built was assembled.
Thereafter 5 years is a good time to replace the battery. On a desktop,
it's an easy job. On a laptop or notebook, it's often a bitch.

VanguardLH wrote in :

NY wrote:

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?

My system has 24 GB of memory, and I have never seen it use more than 10
GB. In a case like this, how much is the page file actually used? I know
windows stores some things there that one wouldn't normally think would be
there, but other than that in a situation like mine will Windows page at
all?

"VanguardLH" wrote in message
...
His Xeon processor
probably supports the virtualization feature (the latest ones do but I
don't know about his), so the question is why it got disabled requiring
him to reenable it. His PC is probably over 5 years old and should have
its CMOS battery replaced.

Thanks for the reminder about the CMOS battery. The PC is probably about
8-10 years old, so due for a new battery, especially as it wasn't used much
for a few years so the CMOS will have been powered only by the battery with
no periods of on-time when the PSU would have powered it. I don't *think*
I've replaced the battery since the PC was new.

I think I saw something either in the BIOS help text or the user manual
which implied that the default state was for virtualization to be turned
off. Would it cause problems for older operating systems if it was turned
on? The PC came with XP (not sure whether it was home or pro).

Wolf K wrote:

Tim wrote:

NY wrote:

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?

My system has 24 GB of memory, and I have never seen it use more than 10
GB. In a case like this, how much is the page file actually used? I know
windows stores some things there that one wouldn't normally think would be
there, but other than that in a situation like mine will Windows page at
all?

FWIW, I have 16GB RAM here, and the last time I checked the size of the
page file it was zero. Win 8.1 Home 64 bit.

You can use the Resource Monitor (filter on pagefile.sys) or
SysInternals' Process Monitor (just file system events for pagefile.sys)
to see if, when, and what is using the pagefile.

You can use SysInternals' RAMmap to see what is allocated in system
memory. Click on the Use column to sort by the type of usage and scroll
all the way down until you reach memory chunks that are Paged Pool.

https://docs.microsoft.com/en-us/win...y/memory-pools
"The paged pool consists of virtual memory that can be paged in and out
of the system."

I'm at home so don't have a Win10 host to look at. On my home Win7
host, Task Manager's Performance tab show 387MB for Paged Pool (which is
configured to a "system managed" /reserve/ of up to 13GB which is close
to the recommended 1.5*N manual setting). That's now with my computer
mostly idle except to compose this message while my NNTP client is
running and with RAMmap and Chrome loaded. When I unloaded RAMmap and
Chrome, the Paged Pool dropped to 384MB. I'd have to use Procmon or
ResMon to see what happens when I run my games or during an image
backup. The reserve is not the current allocation and 384MB of disk
space for the pagefile is puny on a 256GB SSD and even more puny on a
1TB, or larger, HDD.

https://support.microsoft.com/en-us/...it-versions-of

You may not need a pagefile *if* you highly overexceeded the maximum
memory requirement you will ever experience in your current setup. Of
course, all that unused memory is wasted memory, especially if it is
never used. Crash dumps record the contents of memory. 16GB and 24GB
is a lot to read, and how do you read it without using it at the same
time?

Although we are discussing this in a Windows 10 newsgroup, there has yet
been no mandate that this newsgroup discuss only 64-bit versions of
Windows 10. There are 32-bit Windows 10 users.

https://support.microsoft.com/en-us/...ent-in-windows

If you don't allocate a pagefile, there can be problems even if you have
gobs of physical system RAM. If you end up not using any disk space for
a pagefile under your typical loads on your computer then you've lost
nothing by allocating a pagefile, have you? You allocated /reserve/
space on the disk for a pagefile but don't use any actual disk space if
your gobs of system RAM are always sufficient. You lose nothing by not
using a pagefile but you gain safety by allocating the reserve for one.

Side note:
Burroughs acquired Sperry back in 1986. I wish Sperry had refused the
buyout: Sperry was in the black and Burroughs severely in the red, so
Sperry got dumped with a huge debt load. The company name changed to
Unisys: a stupid name that might've looked good on paper but we then
became Uni-sissies. The Burroughs OS would hang when it ran out of
physical memory. Testing was a lot more thorough at Sperry than at
Burroughs. When you wanted to most heavily use it, bang, it died.
Don't ask for the details because I was lucky enough not to be one of
the poor Unisissies that had to work on any of the Burroughs boxes, so I
don't know what was the fix back then.

VanguardLH wrote:


However, the OP got all of his system RAM available by changing a BIOS
setting: enabling the VT-x virtualization option.

But virtualization itself doesn't do that.

At least one chipset in that family, supports
memory mirroring on two branches of four channels
of FBDIMM memory. That's like RAID 1, only for memory.

P X Q X
| | | |
X X X X
| | | |
Quad channel Northbridge

In the diagram, if an uncorrectable ECC error
was detected on "P", then the chipset can use
the value seen on "Q" as a replacement. This
configuration also cuts memory bandwidth in half
(as seen at the processor itself)

When mirroring is disabled, it's just a regular quad channel
chipset again. Since it's an ECC chipset, it can still
correct errors on the DIMMs (at least until too many
errors are present, and the location is "uncorrectable").

X X X X
| | | |
X X X X
| | | |
Quad channel Northbridge

Mirroring happens to cut RAM in half.

Memory mirroring, as a feature, should have its
own line in the BIOS. It should not be toggled
on and off via a virtualization setting.

I don't want to leave people with the impression
that a virtualization setting has "consequences".
Normally, if you aren't aware of what virtualization
is for, the setting can be on or off, and you
would not care or even notice. These features
are normally innocuous (until you need them).
Then some software complains you don't have it
or it isn't turned on.

Paul

On Tue, 13 Nov 2018 14:21:08 -0600, VanguardLH wrote:

If you don't allocate a pagefile, there can be problems even if you have
gobs of physical system RAM. If you end up not using any disk space for
a pagefile under your typical loads on your computer then you've lost
nothing by allocating a pagefile, have you? You allocated /reserve/
space on the disk for a pagefile but don't use any actual disk space if
your gobs of system RAM are always sufficient. You lose nothing by not
using a pagefile but you gain safety by allocating the reserve for one.


Moreover, if you don't have a page file, you can't use all the RAM you
have. That's because Windows preallocates virtual memory in
anticipation of a possible need for it, even though that allocated
virtual memory may never be used. Without a page file, that allocation
has to be made in real memory, thus tying up that memory and
preventing it from being used for any purpose.

Paul wrote:

VanguardLH wrote:

However, the OP got all of his system RAM available by changing a BIOS
setting: enabling the VT-x virtualization option.

But virtualization itself doesn't do that.

Yet the OP reported that the "hardware reserved" memory went away, so he
could use it all. I don't know what BIOS the OP has or it there is a
dependency in that BIOS. I didn't think virtualization would be the
cause, so I never mentioned it but did say that it was likely something
in BIOS that was preventing the OS from accessing all the system RAM.

Ken Blake wrote:

if you don't have a page file, you can't use all the RAM you
have. That's because Windows preallocates virtual memory in
anticipation of a possible need for it, even though that allocated
virtual memory may never be used. Without a page file, that allocation
has to be made in real memory, thus tying up that memory and
preventing it from being used for any purpose.

Yes, once my PCs got to the point of having "big" memory (i.e. 8, 16 or
32GB) I got into the habit of thinking a page file was no longer
necessary other than for crash dumps, but now I do prefer to have a
small (e.g. fixed 2GB) page file, which means that the "junk startup
services" get to sit idle consuming page file, rather than sit idle
consuming physical memory,

"VanguardLH" wrote in message
...
Paul wrote:

VanguardLH wrote:

However, the OP got all of his system RAM available by changing a BIOS
setting: enabling the VT-x virtualization option.

But virtualization itself doesn't do that.

Yet the OP reported that the "hardware reserved" memory went away, so he
could use it all. I don't know what BIOS the OP has or if there is a
dependency in that BIOS. I didn't think virtualization would be the
cause, so I never mentioned it but did say that it was likely something
in BIOS that was preventing the OS from accessing all the system RAM.

I'll boot the PC into its BIOS tomorrow and make a note of any version
number. I'm almost certain that it is branded "Dell".

The User's Guide says (page 79): "Virtualization (Off default) Specifies
whether a virtual machine monitor (VMM) can utilize the additional hardware
capabilities provided by Intel Virtualization technology."

The manual is dated August 2007.