Memtest failure causes

[Greyhound]

I'm having a lot of difficulty getting my rig to pass memtest:

I'm using an Opteron 165 (default of 9 x 200 = 1800Mhz) with some Crucial ballistix DDR500

if I drop the multi down to 4 I can pass memtest for over an hour at 250Mhz mem speed using the specified DDR500 timings, and again for over an hour at 200Mhz using the specified DDR400 timings. All of this is at 2.8v vdimm.

At 250 X 8 and 250 X 9 I get hundreds of errors within a few seconds. Increasing the CPU voltage from 1.38 to 1.45 did not seem to help at all.

I left memtest running overnight using a HTT of 270 and a divider to keep the RAM at DDR333, so that the cpu was overclocked to ~2.4Ghz. This morning there were 4 memtest errors.

I dont really know what to try next? I'd like to think that rather than having the Worst. Opteron. Ever. it's more my lack of knowledge about overclocking that's holding me back.

Any suggestions would be greatly appreciated!

 

[Greyhound]

have you upped the memory voltage to 2.9v?

Not yet - I will try this though. I'm not totally clear on why I would need to do this when I am trying to up the cpu freq. though? I would have thought that CPU voltage was the factor here. Oh well, you learn something new every day!

- Did you lower the HTT multi to 3x ?

I lowered the HTT multi to 4x, which should give 250*2*4 = 2000Mhz, which is what I thought is the target for Socket 939? I didn't think that it would boot lower but I will try this.

- Feel the memorysticks with a finger when running under load, if the sticks are scorching lower the VDimm or actively cool the sticks.

The memory is hardly warm to the touch after an hour or so of Memtest. I'll check it out tonight after a few hours.

 

[Greyhound]

I found that my Ballistix does not respond well to increased voltage or higher/slower timings.

The Memtest errors you got, at what test did they happen?

When it errors really quickly they occur in test 1. The 4 errors that I got overnight were in test 7.

 

[Greyhound]

Interesting!

I'll try 2.9v for now then. If Memtest is ok overnight should I move on to Prime?

 

[Greyhound]

Strange thing is though that Ballistix isn't memory that responds well to >2.8V and you also have to remember that Ballistix had a high failure rate that was possibly linked to high voltage but try it and see.

Yeah I heard about that. The problem is that I dont think I can RMA it if it's ok at stock with the cpu underclocked. I'm really at a loss as to what to do!

 

[Greyhound]

if you can run at 4x250Mhz 1:1 without error and 8x250Mhz 1:1 fails that points towards the CPU, especially as that produces errors in the first test that are CPU related.

What cooling have you got?
Perhaps your mobo is undervolting the VCore a lot?

Here's my rig:

Opteron 165
ThermalTake Big Typhoon
DFI UT NF3 Ultra D
2 x PC4000 Ballistix
Gigabyte X800 Pro (Unlocked to 16 Pipes)
Echo Mia Midi
36gb WD Raptor
3 x 200gb Seagate 7200.7 (RAID 3 on a NetCell SyncRaid)
Antec NeoPower 480w


The motherboard shows about 33c under load at stock and the heatsink is not at all warm to the touch.

Maybe my voltages are fluctuating badly? I have a digital multimeter but I dont know how to test the voltages on the board

 

[Greyhound]

Have you got a BIOS that supports a dual core Opteron, maybe it isn't recognised properly and therefore not working stable?

Have a look at this thread as it offers a bootable BIOS CD to update your BIOS:
http://www.dfi-street.com/forum/showthread.php?t=22031

Yeah I am running the C19 Beta bios - it's the only one with Opteron support. I was thinking of flashing to an older bios, but wasn't sure what the repercussions of using a bios that doesnt recognise the cpu would be...