passing memtest86, but not prime stable at all

[Snowice]

i have 2 sticks of 512mb kingston khx3200a. they can pass memtest86 for 8+ hours, but cant prime 95 at all. there is no error at ddr440 in memtest86, but will fail prime in minutes. I'm sure it's the memory cuz I had my cpu underclock. at stock speed, they are stable for both memtest86 and prime at 2-3-2-6 tho. i know ch-5 is not very good for overclocking, but why they can pass memtest but not prime?

 

[Budman]

but why they can pass memtest but not prime?

Because prime95 test the CPU and memtest test the ram,looks like your cpu is unstable.

What are your system specs? mobo/psu .....

 

[Fern]

Originally posted by: Snowice
i have 2 sticks of 512mb kingston khx3200a. they can pass memtest86 for 8+ hours, but cant prime 95 at all. there is no error at ddr440 in memtest86, but will fail prime in minutes. I'm sure it's the memory cuz I had my cpu underclock. at stock speed, they are stable for both memtest86 and prime at 2-3-2-6 tho. i know ch-5 is not very good for overclocking, but why they can pass memtest but not prime?

I don't think 8 hrs is enough. I was going for FSB 220, memetst86 got to 20hrs and I was about to conclude it was stable then an error popped up. Upped the vdimm and it failed gain in 4 minutes. Go figure.

Also, P95 does test ram, depends on which P95 test you select.

Fern

 

[Snowice]

Originally posted by: Budman

Because prime95 test the CPU and memtest test the ram,looks like your cpu is unstable.

What are your system specs? mobo/psu .....

here is my spec....

amd 64 3000+ 939
gigabyte nforce3-ultra 939
fortron 530w psu
160g wd sata hd
ati 8500le (for now)

no, my cpu is stable... i had it up to 2400 mhz (9 x 267) w/ a 133 memory divider prime stable for 10+ hours. but using a 3:2 divider is such a performance hit... ram is only running @ 177. when i used a 166 divider, my ram won't prime no matter how much i relax the timing. they were @ 222 3-6-6-12 w/ +0.2v vdimm.... well, that's the best my mobo can do (max is +0.2v vdimm). so this could be my mobo. but @ 222, my ram passed memtest w/ 2.5-3-3-6 for 8+ hours. go figure 😕 another thing is i got this thing prime stable @ 2400 (8 x 300) w/ 133 divder.... but my mobo can only boot when i increase fsb slowly.... 270->280->290->300. if i try 300, it wont post... even i go to 300, it wont post after i restart..... obviously, i'm not too happy w/ the mobo, neither.

 

[JarredWalton]

SATA hard drives actually can be a severely limiting factor when overclocking. Anything above 220 MHz bus can cause issues in my experience. Prime95 actually stresses the entire system - it writes files on the hard drive frequently, for instance - so that might be the failure point. On my system, I noticed that the SATA connections had been reduced to PIO Mode 4 compatibility (16 MB/s maximum transfer rate) due to my moderate overclock. How do you get around this? Well, that's more difficult to answer. You can try other SATA ports - some of them might not be as picky. You could also try an add-in SATA card instead of the integrated SATA controller.

 

[FlameDeer]

Seem like your mainboard is the culprit. 🙁

Is that update your BIOS version will help?