Mailinglist Archive: opensuse (2483 mails)

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[opensuse] OT: Is the problem the Motherboard or the RAM
  • From: Mike Coan <mikecoan@xxxxxxxxxxxxxxxxxxxxxx>
  • Date: Sat, 3 Jan 2009 14:45:55 -0500
  • Message-id: <200901031445.55372.mikecoan@xxxxxxxxxxxxxxxxxxxxxx>
Getting ready to install opensuse 11.1 on a new machine, or at leat the
motherboard, the RAM, and the CPU are new.

M/B: Asrock AMD A780GXE. this is an AM2+ socket M/B, that supports 8GB of

DDR2 1066, and Phenom CPU
CPU: AMD Phenom quad core 9850
RAM: 4 sticks of 2GB OCZ Platinum DDR@ 1066 RAM. The 4 sticks are actually

two pairs of Dual Channel Memory, all the same speed.

There is also a 475W Thermaltake power supply, 4 SATA II drives and an
aluminum case form the old system. The motherboard includes integrated
graphics, so no graphics card.

The M/B has four DIMM slots. DIMM1 and DIMM2 are dual channel, as are DIMM3
and DIMM4.

I insert all 4 sticks of memory. CPU fan and all case fans spin as do hard
drives. No Post.

I remove 2 sticks, leaving DIMM!1and DIMM2 occupied. All fans and drives spin
no post. I put 2 sticks in DIMM3 and DIMM4. all fans and drive spin, no

I remove stick from DIMM2. Computer boots. BIOS correctly detects CPU and
CPU speed. Identifies memory as DDR@ 800 (not 1066 as manufacturer claims and
is on the memory). Run memtest and memory passes with no errors. Test 2
other sticks in DIMM 1 and both pass memtest with no errors. I test the 4th
stick in DIMM# and it passes memtest with no errors. One thing that is
curious is that from a cold boot memtest rates the memory at DDR2 667. From a
warm boot it rates it at DDR2 800.

I put one stick in DIMM1 and one stick in DIMM3 so that it runs in single
channel mode. Computer boots fine. Thus it posts and boots with 4GB in
single channel mode, but not in dual channel mode. I could find no option in
the bios to disable dual channel mode, so there is no way to test 8 GB in
single channel mode.

I basically left the BIOS defaults, except that I changed the DIMM voltage
from auto to 2.2V, which is what is specified for the RAM. I am not trying to
overclock or anything exotic.

Any ides on a methodology to determine whether it is the M/B or the RAM that
is causing the problem? I do have four sticks of 2GB DDR2 667 RAM in the
production server that I could test, but I am not that anxious to take down
the server. We are a small office and it could be done after hours if need

I suppose I could fiddle with the BIOS and manually set the RAM speed to low
values and see if it posts, but I wanted to seek ideas here before starting
that. By googling I found some indications that if it posts with memory in
one slot but not two it is the M/B, but other posts seem to indicate that Dual
channel memory is sometimes mismatched and can be the problem. My desktop is
an Asrock M/B (different model) with 4GB of dual channel memory and it hasn't
hiccuped once.

Thanks for any feedback.


Michael A. Coan
Woodlawn Foundation
524 North Avenue, Suite 203
New Rochelle, NY 10801-3410
Tel 914-632-3778
Fax 914-632-5502
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