System fails RAM stress test but CPU stress test OK.

I'm working on overclocking a Socket 939 Athlon X2 4400 (2.2 Ghz stock, 1 MB cache each core) and when I run the Stress Prime Orthos test to stress the CPU itself it's fine, but when I do it to stress the RAM I get an error.

Now, I previously had a single core Opteron 148 in this computer and it seemed pretty stable at the same RAM settings and at a much higher overclock than the 4400. The computer has 4 x 512 RAM in it.

Is it possible that the RAM is now undervolted because the 4400 is sucking up more voltage? The voltage readings on my computer show it as being about 0.05 V lower than where I have it set in the BIOS.

Should I up the RAM voltage? It's currently set at 2.8 V. Should I start playing around with the RAM timings? Currently at 2.5-3-3-7 and 2T with a divider of 133/200. (Current CPU overclock is 11 x 225.)

Maybe I should try it with relaxed timings. Runs fine on Stress Prime Orthos at 11 x 200 and 11 x 210 for 10 minutes with the same settings. The RAM has passed a Memtest before.

Is it possible...would it make any sense that the problem is RAM-based even at these lower speeds when it seemed fine with a single core at higher speeds? It seems like the new (to me) dual core CPU needs more voltage in the BIOS to maintain a given voltage on my mobo stats/temp/voltage monitor than the single core Opteron did. Could it be possible that the RAM is getting undervolted now and that even though I have it set for 2.8 in the BIOS that it's lower in reality?

Using a new processor changed the was the BIOS sets timings. Have you cleared CMOS or used the Load Default settings to clear old settings. Try reseating RAM or swapping positions.
It's also possible that some ram ages causing it to fail to run high performance as it gets older. Then yes there is going to be some voltage drop from the 148 to the 4400.
Try running 2.5-3-3-8 that may be all that it needs and you will hardly notice the change.

AlabamaCajun said:

Using a new processor changed the was the BIOS sets timings. Have you cleared CMOS or used the Load Default settings to clear old settings. Try reseating RAM or swapping positions.
It's also possible that some ram ages causing it to fail to run high performance as it gets older. Then yes there is going to be some voltage drop from the 148 to the 4400.
Try running 2.5-3-3-8 that may be all that it needs and you will hardly notice the change.

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Thank you for the warm welcome. I normally spend time at Anandtech and sometimes [H]ardOCP, but I'll probably visit this forum now and then.

I already tried that, though perhaps I should give it another go. Perhaps it's one of the memory controllers on the cores themselves. It seems to be stable at 11 x 220 (2.42 Ghz) and 1.525 V (lower readings of actual voltage from mobo) with a 133/200 RAM divider.

Still, having come from a single core Opteron 148 that ran cool at 11 x 250 (2.75 Ghz) with the same RAM settings, this is pretty disappointing.

Whippersnapper said:

Thank you for the warm welcome. I normally spend time at Anandtech and sometimes [H]ardOCP, but I'll probably visit this forum now and then.

I already tried that, though perhaps I should give it another go. Perhaps it's one of the memory controllers on the cores themselves. It seems to be stable at 11 x 220 (2.42 Ghz) and 1.525 V (lower readings of actual voltage from mobo) with a 133/200 RAM divider.

Still, having come from a single core Opteron 148 that ran cool at 11 x 250 (2.75 Ghz) with the same RAM settings, this is pretty disappointing.

Click to expand...

I visit Anandtech some but find it friendlier here though thread wars break out they solve them quickly.

You may find it necessary to work out the HTT and CPU Multi to get the ram around DDR420 to get the best results but you should be able to do 2.6 or better is you can cool it. If you go back on the archives here you might find some of the results from the early Manchester days.

This one is a Toledo. It's been stable at 11 x 220 for a couple days now and perhaps the Arctic Cooling Ceramique thermal paste has cured and settled. Might start pushing it up by 1 Mhz/week soon.