Re: ASUS P4S800D-X Memory Configuration Problem

In article <m9AEf.446823$vC.145477@xxxxxxxxxxxxxxxxxxxxxx>,
no@xxxxxxxxxxxx (marcbkk) wrote:

Paul, thank you. What you say makes real good sense. What is strange
though is that the board wont even run using just two modules, of one
of each kind.

If your theorey holds true, then it would seem I should be able to run
the one 1GIG module on one of the blue DIM sockets for example and
then one of the 512MB modules on on of the black DIM sockets.

This one of each configuraiton did work when I was running the other
ASUS board which had just two RAM slots. Granted the other board had
an Intel Chipset and this one is SIS, but I don't think that should
make so much of a difference.

I think I am going to return to the shop and see if they will exchange
the 1GB module they just sold me for two more 512MB modules. Then I
would have a total of 4 modules running instead of 3 and all 512MB.
It would seem this should work evne though they would be different
brands.

My only fear is it may not work as well becuase, as I said, I already
tried running one of each of the brands together already and it did
not work.

Maybe though it didn't work becuase the two modules I tried running
together, one of each brand, were different sizes in terms of
memory.

Hard to speculate I guess. Trial and error and maybe more error!! :)

I had a look here, and it looks like not all four stick configurations
are working. (Set the menu to "All days", to see as many postings
as possible.)

http://vip.asus.com/forum/bbs_topic.aspx?board_id=1&model_name=P4S800D-X

"I have 4 sticks of Kingston 1GB DDR400 PC3200 Memory and the
problem I have is that in the bios it shows 4GB¹s installed
but it is only using 3GB¹s? And when i look in windowsXP it
also shows only 3GB."

So four identical 1GB sticks work.

  "I tried to put 4 sticks of Corsair 512mb D400 CMX5123200C2 in
my machine and it boots to windows xp and then goes to a blank
screen. Nowhere does it say you can't run 4 sticks of memory in
the book. Why do they show you haow to install 4 sticks and also
have 4 slots to put them in if you cannot use all 4? terrible.
cost me restocking fee to send 2 back. Now to upgrade to 2 Gig's
of ram I have to pull out the 2 sticks of 512ram andbuy 2 sticks
of 1Gig ram?"

So that guy put four identical CAS2 512MB sticks and the computer POSTed,
but Windows would not work. Perhaps a timing adjustment and testing
with memtest86+ would have resolved the problem.

This one is a little too large to copy, but the only configuration
that sort of works is three sticks. This posting is not too
encouraging.

http://vip.asus.com/forum/bbs_view.aspx?board_id=1&model_name=P4S800D-X&message_id=20060131053824961&filter=5&page_size=100&elite=0&SLanguage=en-us&topic_page=1&page_cnt=2&recc=132

This entry on the Asus FAQ page is strange:

http://support.asus.com.tw/faq/faq_right_second_detail.aspx?kb_guid=4CDFEAB4-34CA-4E66-233E-2F79C525AF2E&SLanguage=en-us

"Question

Does ASUS P4S800D/P4S800D-X support Dual Channel Symmetric and
Asymmetric memory?

Answer

Yes, both Dual Channel Symmetric and Asymmetric memory modes are
supported by P4S800D/P4S800D-X.

When two channels are populated with the same amount (MB) of
total memory, the memory access mode will run at 128Bit*1 Dual
Channel Mode.

When two channels are populated with different amount (MB) of
total memory, the memory access mode will run at 64Bit*2 Dual
Channel Mode."

The implication of that FAQ message, is that your original memory
configuration should have allowed the computer to POST...

From Hothardware -

http://www.hothardware.com/viewarticle.aspx?articleid=162&catid=3

"SiS655FX w/SIS964

Integrated High Performance Dual Memory Controller
- Delivering up to 6.4GB/s Bandwidth
- Performance optimization auto-configurability with
flexible granularity via supporting the Dual 128x1
bit mode in symmetric DIMM types deployment, and the
Concurrent Dual 64x2 bit mode with flexible DIMM
types support
- Up to 4 DIMMs of DDR400/DDR333
- Support Un-buffered DDR DIMM and up to 1GB per DIMM"

OK, I interpret the keyword "concurrent" to mean the
memory controller can run the two channels independently,
in a limited sense like Nforce2. Perhaps if you had gone
to the BIOS and selected

"128 Bit Access Mode" [64*2]

before you added the RAM, the board would have POSTed ?

Also, the most conservative settings would have been to
use Command Rate 2T, at least until you can get the computer
running. I would use 2T for both channels, if using more
than two DIMMs. Set to 2T before adding more than two DIMMs.

Ch0 MA 1T/2T Select [MA 2T]
Ch1 MA 1T/2T Select [MA 2T]

Based on doing a bit more reading, it sounds like the
chipset is a little more flexible than the Asus motherboard
manual implies. The real question is whether the Asus BIOS
is holding the motherboard back.

(_Should_ work with three DIMMs!)
http://www.ocworkbench.com/2003/sis/655fx/655fx-1.htm

I think I was too quick to judge your situation earlier, as
it appears this motherboard's BIOS is a "can of worms".

The testing sequence I would try:

1) Test the 1GB module by itself. Does it work ? Get a
copy of CPUZ, which has an option to dump information
about the DIMMs (www.cpuid.com). The text file output
should have lots of info on the DIMM, and also includes
a dump of the contents of the SPD on the DIMM.
2) Test the 512MB modules separately. Do they work by
themselves ?
3) Now insert 512MB in A2 and 512MB in B2. That should be
a dual channel mode capable of supporting "128*1"
mode preferably. The "128*1" mode is faster than "64*2".
With a single DIMM in matched socket locations, the board
should support 128*1 mode and MA 1T on both channels.
4) Now you are going to reconfigure things. Before shutting
down the computer, enter the BIOS and set memory mode
manually to "64*2" and MA 2T on both channels. Strictly
speaking, for this experiment, you could use MA 1T on the
channel with only one DIMM in it, but considering the
stability of the BIOS, that is not likely to be a good
idea. MA 2T on both channels is safer. Test that the
computer still starts and boots properly with the new
settings. Now shut down and install the new memory
configuration. Put 512MB in A1, 512MB in A2, 1GB in B1.
That balances the total quantity of RAM in the two channels.
I am hoping, that by setting 64*2 mode in advance of
installing the RAM, the computer will POST.

In terms of memory configurations and memory bandwidth,
these are the levels of performance I would expect:

512MB in A2 and 512MB in B2 - supports 128*1 and MA 1T - fastest
1GB in A2 and 1GB in B2 (same as the first config)

four identical sticks - supports 128*1 and MA 2T - slower

512MB in A1, 512MB in A2, 1GB in B1 - supports 64*2 and MA 2T
- slowest of the three configs

When you go to the shop tomorrow, somehow arranging to get
2x1GB would be the fastest. Going 4x512MB is only a bit slower.
Using the three DIMM configuration, assuming that setting the
BIOS manually would make it work, would be the slowest, and
according to one benchmark I read, in three DIMM mode the
chipset performs like an Intel 848 single channel board.

I hope that isn't too confusing. Even with all of the theories
expressed above, the vip.asus.com forums contain a few
postings of configurations that should have worked and did not.
So, things may or may not work out for you.

Post back with your progress,
Paul
.

Relevant Pages

  • Re: memory bank, rank and channel
    ... Memory chips use those three dimensions for internal addressing. ... If you have a 512MB DIMM, it might have 8 chips on each side ... "Channels" are independent memory interfaces on a Northbridge. ...
    (alt.comp.periphs.mainboard.asus)
  • Re: FBDIMM vs DIMM - any compatibility?
    ... Does the 2950 *REQUIRE* the FBDIMM type of memory? ... I'm afraid FBDIMM and DIMM are completely differently electrically, ... the four channels don't have the same amount of memory on them. ...
    (comp.arch)
  • Re: + edac-new-opteron-athlon64-memory-controller-driver.patch added to -
    ... So we can kill the processes using that memory. ... What is the chipsets idea of which DIMM the memory error occurred on. ... There has always been enough information to determine the hardware ... some that are not easily accessible to user space so a kernel driver ...
    (Linux-Kernel)
  • Re: PC-DL Deluxe memory question
    ... Also I was looking at the 875p chipset memory configuration guide, ... The "Memory Technology" is the size of the individual memory chips, ... That is two banks of chips, ... If the 2GB DIMM was half-populated ...
    (alt.comp.periphs.mainboard.asus)
  • Re: Setting a partition on Mac HD
    ... A PC100-333 DIMM will require three bus cycles for a random access (30 ... The delays are actually characteristics of the memory, ... will work in computers which support both speeds (as long as the ...
    (comp.sys.mac.system)