phenom II x4 965 BE hypertransport bug ???

Discussion created by maxreason on Sep 2, 2009
Latest reply on Sep 9, 2009 by avk
phenomIIx4 965 BE hypertransport must be reduced to 1600MHz with winxp64 ???

I built a new system with phenom II x4 965 BE and gigabyte motherboard GA-MA790FXST-UD5P running windows xp 64-bit edition, but the system would freeze every 1 to 20 minutes at random times (including when no task was running and nothing was happening).

I'll skip the 3 days of careful and thorough tests I ran, but it included running memtest86+ for hours from boot CD generated (zero errors), removing everything except video card from the motherboard slots, trying other memory modules, underclocking the CPU from 3.4GHz to 2.4GHz, underclocking the 1600MHz memory modules to 800MHz, and so forth.

For some odd reason the BIOS sets the northbridge/hypertransport speeds to 2000MHz instead of the 2600MHz that this CPU and chipset should support, so that should have been very conservative.  Nonetheless after I had tried everything else I downshifted via BIOS the northbridge/hypertransport speeds from 2000MHz to 1600MHz --- and the system became completely reliable, stable, solid thereafter (for 2+ days so far).

Thinking the motherboard and/or northbridge chipset must be defective (slower than specification) I ordered a new motherboard.  I figured this would surely solve the problem.  Today I got the new motherboard and found it has ***exactly*** the same problem.

My question is --- where is the bug?

I am certain AMD chip testing tests the hypertransport bus on their CPUs at the full 5200MT/s hypertransport v3.0 speeds, so I tend to believe the CPU is not defective.

That leaves two possibilities that I can think of:

#1: Something is fundamentally wrong with this motherboard.

#2: Some code in Windows XP 64-bit edition malfunctions when the northbridge/hypertransport speeds exceed 1600MHz.

To me, #1 seems quite unlikely for the following reason.  I chose this motherboard because most reviews of the Phenom II x4 965 BE CPU were performed on this motherboard --- and none of them reported any problems with flakiness in general or the northbridge/hypertransport in particular.  In fact, many of these reviews overclocked the various parts of the system to see what kind of performance they could achieve.

That leaves #2, which seems somewhat unlikely too --- but what other possibilities are there?  Am I missing some more likely possibility?  Obviously there is one other possibility:

#3: The CPU chip I have was not properly tested, or malfunctioned within the first 15 minutes of running in my system.  That seems highly unlikely to me, but it is possible.

Q1: Does anyone else run this combination of <CPU, motherboard, OS> with northbridge/hypertransport at 2000MHz to 2600MHz (or higher)?

Q2: Does anyone see any other possibilities that did not occur to me?

PS: The CPU temperature never exceeds 41C, the system temperature never exceeds 41C, the GPU temperature never exceeds 51C, and the system has lots of fans and excellent airflow (and the fans always run at full speed).  The problem is no more likely to occur with lots of CPU activity versus minimal activity.

#####  system specifications  #####

motherboard: one gigabyte GA-MA790FXT-UD5P
CPU: one 3.4GHz AMD phenom II x4 965 BE (black edition)
DRAM: four mushkin 996601 modules (4 x 2GB DDR3-1600MHz @ 7-7-6-18)
video: one evga nvidia GTX 285 with 2GB VRAM
disks: two seagate 1TB SATAII drives (ST31000528AS)
disks: one western-digital 1TB SATAII drive (WD10EADS-00M2B0)
CDDVD: one NED CD/DVD burner (ND-3540A)
power: one coolmax greenpower 950W (CUG-950B)
CPU-cooler: zalman CNPS9700
fans: eight 80mm ball-bearing fans running constantly at full speed

NOTE:  the DDR3 memory is running at 800MHz to 1333MHz @ 9-9-9-24
NOTE:  often the tests were run with only one hard disk drive connected

PS:  Reply here or send reply to <maxreason at gmail dot com>.