F2-6400CL5D on M4A785-M refuses to run at 400mhz

[adenosine]

Model of the motherboard: Asus M4a785-M
Model of the memory: F2-6400CL5D-4GBNT
Model of the CPU: Althon II x3 445

I just built this system and am running everything at stock speeds, and I noticed my games weren't stable. So I decided to test stability with Prime95. It fails within 10 minutes of a 'blend' test. It will run for hours on the 'small FFTs' test that doesn't test memory very much.

Pinning down what's causing it to fail has been difficult....

Over 8 hours of testing with Memtest86+ failed to return any errors
If I run the memory at 333mhz instead of 400mhz, it becomes stable
If I turn off all my cores except one it seems to become stable
If I remove my video card and start using my integrated video on the motherboard it seems to become stable (would this have any effect on the memory because now it has to use my memory for the video?)

I don't have any known good memory to swap out because my old system didn't use DDR2 memory. I'm thinking it's something memory-related just because it works rock solid at 333mhz, but is there any way to make sure? I don't want to RMA the wrong piece of equipment.

[Tradesman]

You may need more voltage to the CPU and CPU/NB than they are getting in order to allow the MC (Memory Controller) to be able to run the DRAM at 800...could you post your DRAM settings and system voltages

[adenosine]

I have everything set to 'auto', except the memory frequency. I wasn't sure what that auto sets things to, so I installed the ATI Overdrive util that can read that stuff...




The cpu voltage seems to be really low b/c of 'Cool n Quiet'. I noticed it would go up and stay at 1.4v if I ran tests. 1.95v memory? The package says 1.8v.....

If I change the memory voltage manually in my bios to 1.8v, Windows will blue screen before I log in.

333mhz at 1.8v seems perfectly stable, however...



It won't let me up the juice anymore in the utility, so I assume 1.4v is as high as the CPU is supposed to go. I can't even get into windows at the correct voltage and frequency for the memory to test if getting the northbridge voltage up works...

[GSKILL TECH]

Do you have the latest BIOS?

Thank you
GSKILL TECH

[adenosine]

My BIOS version is 1006, which is the latest one available on the ASUS website.

[Tradesman]

What do your sticks show in the actual BIOS for their base timings? Above it shows 5-3-5-15 when it should be 5-5-5-15

[adenosine]

My BIOS doesn't tell me what 'auto' sets things to. That's why I installed the utility. Note that the pictures here show 1.8v manually set because I was a little worried after I saw how much juice 'auto' was giving them.




However, I don't think that the images show my timings being wrong. The box on the left on the first picture is the timings that were read from the memory as being 'correct'. The box on the bottom right is the timings in use, which show 5-5-5-15.

[Tradesman]

May want to try loading them all manually, 1.8 to 1.85 for DRAM voltage, base timings to 5-5-5-15 and CR (Command Rate) to 2N or 2T depending on how it shows it (some use the T others use the N designator

[adenosine]

I tried running them at 5-5-5-15 and 6-6-6-18 manually in the BIOS. Neither one was stable.

There doesn't seem to be a command rate option I can set. No option in the timings had an option of 2T or 2N.

[GSKILL TECH]

Send them in for RMA to see if a new kit works better. You should not have such problems.

Thank you
GSKILL TECH