Overclocking problem

[acstech]

Ok, so I have this system I just built:

Athlon X2 4000+ 2.1GHz
Biostar T-Force 7025-M2
2GB Kingston DDR2-800
Samsung 250GB HD
Samsung DVD-RW
AcBel 550w PSU

Here is the problem. I can overclock it fine to about 250fsb. I set the max ram speed in the bios to DDR2-667, which results in an actual memory frequency of about 375MHz, or somewhere in there. Then I lower the HTT multiplier to 4x. After setting the voltages for everything correctly, it will all pass Prime95 (the new dual threaded version) nicely. Above 250fsb things don't work too well. But that's ok, 250 would be enough.

The problem is that pretty much anything above about 210 I get this strange problem. While it will all pass Prime95 for many hours, if I shut the system down and turn it back on, it will just sit there and beep at me like it has a memory error. The one long beep followed by silence, then another long beep, and so on. At which point, I need to reset the bios via jumper.

Things of interest:
CPU stepping as best I remember it: NAA4G-0806BAG, Made in China
Motherboard is a new revision, 5.1. The other 7025 boards I've used have all been version 5.0, and have all had a stable FSB up to at least 300MHz.
Memory read speeds in Everest seem a bit low for the timings and speed it's running.

Any ideas? I have a test computer with very similar hardware, I may start swapping and try to see where the problem is.

[acstech]

Re: Overclocking problem

Update:

It just did it again at stock speeds. Everything set to normal.

[acstech]

Re: Overclocking problem

It appears to have been the memory. I swapped that out and the problems seem to have gone away. Funny that it passed Prime95 but still had problems.