Re: Continuous beeping and Machine_check_exception STOP:A 0X000000

Terry wrote:
LOL Jose :) What you suggest is exactly what I have done and yes it posts and all the ram is used. I still can't change the boot device and I expect to continue getting the machine stop errors until I can figure this out but hey . . at least I am running!


You know, that the RAM population rules, change with processor stepping ?
That means, the content of your Gigabyte motherboard manual, would
have needed to be amended, after the E0/E3/E4/E6 processors came out.

This is your CPU support chart. Only one of the two possible 4400+ S939
processors is in the chart. (Asus is the best at keeping track of the
processors and describing them. Some of the worst companies, give no
individual detail about what processors are supported or tested.)
You would think revision F1 BIOS would be good enough, but you
never know.

http://www.gigabyte.com.tw/Support/Motherboard/CPUSupport_Model.aspx?ProductID=1939#anchor_os

The older processors, like a CG or a D0 stepping, accept a single stick
(in a certain preferred slot, not just any slot). They also accept matched
pairs with the CG and D0 processors. So the allowed amounts of RAM with
those processors, is 1, 2, or 4 sticks, and a single stick only works
in two of the four slots. An "illegal" combination is 3 sticks. And if
there is a hardware defect in your system, which causes
a stick to be ignored, the result might be a 3 stick configuration.
The Gigabyte manual, and the memory tables, properly reflect a
CG or D0 processor.

Anything which is E0 or higher, is different. E0 accepts 1,2,3, or 4
sticks of RAM. They don't have to be matched, because the processor
can operate in a virtual single channel mode. Certain configurations
(the matched pairs thing, with two or four sticks), work to give
better performance. If you insisted on using 3 sticks with a processor
like that, it should work, but it might not have as high a memory
bandwidth benchmark result.

A reference to revision E is here.
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/26094.PDF

PDF page 30

"Revision E

Function 2, Offset 90h, Burst2Opt (bit 5), Mod64BitMux (bit 6... "

The Mod64BitMux bit was added to processors of Revision E or later.
That is the bit that would be used by a sufficiently modern
version of BIOS, to allow 1,2,3, or 4 mismatched sticks of
RAM to work in your motherboard. The bit only needs to be
enabled, if there isn't a nice set of matched pairs involved.
See the bottom of PDF page 107 in the AMD document, for a
description of "Mod64BitMux". If your BIOS cannot deal with
3 sticks of RAM, then you know your BIOS is not ready for
an "E" processor.

Looking at the downloadable manual from Gigabyte (motherboard_manual_k8n51gmf9_e.pdf),
the lower table with the yellow caution symbol, is no longer appropriate for
an "E" processor. All possible configurations should work with "E".

ftp://download.gigabyte.ru/manual/motherboard_manual_k8n51gmf9_e.pdf

So which configurations still cause problems ?

These are the settings typically used for a system like that. In
this example, the memory is all PC3200 (DDR400) stuff. These
are the operating conditions for using up to four sticks of
that memory.

2 DIMMs (dual channel, matched) DDR400, Command Rate 1T

4 DIMMs (dual channel, matched) DDR400, Command Rate 2T
4 DIMMs (dual channel, matched) DDR333, Command Rate 1T

The BIOS will typically switch to DDR333, Command Rate 1T, if
there are four DDR400 sticks present. They select that setting,
because of bus loading. Many users don't like to see the BIOS
do that, and those users will attempt to use
"DDR400, Command Rate 2T" instead, to make themselves feel
better. Operating at DDR400 gives a slight advantage, but
not enough for the level of excitement seen in discussions
about this topic.

The manual is coy about discussing advanced memory settings.
For example, see this comment.

"Answer: Some advanced options are hidden in new BIOS version.
Please press Ctrl and F1 keys after entering BIOS menu and
you will be able to see these options."

Since the memory options are not documented, because they are
"advanced", I cannot give an exact recipe for how I'd tune
your system. This will give a rough idea.

Four sticks, matched.

1) Select DDR400
2) Set the Command Rate to 2T.
3) Set DDR DIMM voltage (VDIMM) to 2.7V if available
4) Adjust timing, like set Tras one unit higher, if the
memory is not stable. Check the RAM SPD tables with
http://www.cpuid.com/cpuz.php , and figure out which
timing is the common denominator. For example, if the
slowest stick is 3-3-3-8, use that for the timing
values. Tcas-Trcd-Trp-Tras.
5) *Don't* boot Windows, until you've run a few passes of
memtest86+ to prove the memory works. Memtest86+ also
has a bandwidth indicator at the top of the screen, which
can be used for comparing the various ways of installing
memory (so you can compare the bandwidth difference between
using one stick and running dual channel).
6) If you're satisfied the memory settings aren't a total
disaster, boot Windows or Linux, and run Prime95 for
a few hours. If errors are detected in ten minutes or
less, you have more tuning to do. When I'm tuning, I use
my Linux CD, because it cannot be corrupted.

Windows Prime95 Stress test for memory and CPU.
http://majorgeeks.com/Prime95_d4363.html

In addition to tuning memory in the BIOS, there is at
least one utility someone wrote, which allows changing
settings in Windows on the fly. Obviously, such a
practice is dangerous. The value of Tcas cannot be
changed in that case, because you're not allowed to
change that on the fly. It is normally set in the BIOS
during POST, and is not supposed to change. I don't
remember the name of that utility, but if you run
out of other options to try, to get at the adjustments,
I'll have a look around and see if I can find it. See
if control-F1 works in your BIOS first, as then
you're likely to get into less trouble.

HTH,
Paul
.

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