Java Jive wrote:
As per title, I have an old Dell Precision M4300 laptop with 2 identical
sticks of Crucial CT25664AC800 16 FHZ 2GB DDR2 SODIMM PC2 64 RAM.
Running the RAM test from the Ubuntu 16.04 64-bit grub boot option, each
stick passes individually in Slot 1 (under the keyboard), but together
one in each slot they fail, and the PC won't boot with a stick only in
Slot 2, behind a cover on the base of the laptop.

A Google search didn't find much that was useful. Any suggestions as to
what may be wrong?

TIA

There was a problem with the bottom slot here as well.

https://www.dell.com/community/Lapto...d/td-p/4150560

*******

See if the BIOS has any setting for clearing
DMI/ESCD. The BIOS "remembers" the DIMM inventory
and other hardware items. Any time the hardware
installation changes, the DMI/ESCD is rewritten.
There used to be some kind of problem with that
years ago. It's not a common problem today, as it
doesn't come up in conversations any more.

Tools like DMIExplorer could be used to dump or
review the information.

From a technical perspective, it's not critical
to system operation, but it's part of the POST
sequence.

The DMI/ESCD is normally a "one-shot" thing. You
set it, and the next time the machine starts,
the POST clears the request. Normally the process is
fully automated, but sometimes it gets into an update
loop (updates each and every time the machine
starts). Then, perhaps, the one-shot BIOS request
feature, might knock it out of that loop.

In some cases, the problem isn't exactly what you'd think.
There can be a bug in the preparation of the memory map.
On one chipset, this involved some register for USB
ports, versus the Top_Of_RAM definition. The screen
of the computer would report "USB Overcurrent".
Reducing the quantity of RAM would make the problem
go away. If testing such a thing in your lab,
you'd try a mismatched pair (a 1GB and a 2GB stick)
and see what happens. If memtest passes, the system
behaves normally, it would then be telling you
there might not be a problem with the slot after all.

Dual channel problems show up with older AMD processor
designs. Two DIMMs had to be "put across from one another",
and the DIMM busses worked like tandem locomotives.
One slot is considered the master on the AMD design,
the other is a slave, and two DIMMs work like a 128
bit or a 144 bit wide DIMM in a sense. Filling the
wrong slot first, doesn't work and the system
doesn't start. Mis-matched DIMMs might start up
in single channel mode. These issues were caused
by minimalist memory controller designs on the
first processors of that generation, and gradually
over time, AMD became as good at dual channel design,
as Intel Flex Memory. Today, nobody thinks twice before
filling an AMD memory slot. (My AMD laptop has mis-matched
DIMMs.)

https://www.dell.com/support/home/ca...iverid=R207161

"Dell Precision M4300 System BIOS, A13

4. Fixed Wi-Fi sniffer function with 4GB memory and Dell wireless.
"

That's the first release I could find, which mentions
amount of memory, and a failure condition.

*******

https://arstechnica.com/civis/viewto...p?f=9&t=106411

"The Dell Upgrades website claims the Precision M4300 will
support up to 8 GB of ram but my machine refuses to boot
with 2 4GB sticks. It just sits there for hours at the
Dell boot screen with less than half an inch to go on
the progress bar.

If I replace one of the 4GB sticks with one of the original
1GB stick, it will boot right up and show all 5GB in the
bios and windows.
"

"BIOS revision is A10 and currently Dell shows an update to A12"

"Edit: Woohoo!! continuum gets a cookie!"

Too bad the images attached, aren't available for review.

This could be solved by another version of BIOS,
at a guess. I don't normally recommend BIOS flashing,
as there's a risk you could always brick the thing.
Brickage wouldn't happen, if the BIOS designers followed
the rules on "boot block". But a number of commercial BIOS
zap boot block and main BIOS block, and if the refill of
the main BIOS block fails, with the erased boot block,
it can no longer bootstrap itself.

If it does brick, then the issue is whether the BIOS chip
is socketed or there is a programming header next to it.
PLCC or DIP flash chips, some are socketed. Those have
no programming header next to the socket. Newer designs
use 8 pin (serial) Flash chips, for which a 7 pin programming
header might be adjacent. A programmer dongle tied to USB
bus on the Technician computer, allows flashing up the
broken chip and fixing a brickage incident.

Paul