I have tried relaxing the timings for my RAM (2.5T-3-3-3-11) and (3T-3-3-3-11) and to no avail. The only difference, in the first timings, got a reboot. The second timings, I got 100 warning message.

Maybe I'm getting closer? (ie. error vs warning?)

have you barrowed someone elses ram... jw

Unfortunately, I don't know anyone that has 2 x 512MB of PC2700 that I can borrow...

Did you already try out using only a single RAM module?

Yes I did. Running Prime95 with 1 dimm (tried with both) worked.

Then I guess lowering the CPU clock won't improve that much. I'd suspect (s)lower memory frequency / timings to be more effective...

3T-3-3-3-11 gets me warning messages rather than hardware errors. Maybe I'm getting closer?

All afternoon, running a FSB of 133Mhz, resulted in a stable system. As soon as I put it on 166Mhz, then I start having random reboots. I think it's time for slightly more expensive memory :D

So far, system is stable at 166Mhz. Seems all I needed was a CMOS wipe (Suggested by Asus tech). So far so good. However, Prime95 still gives me the hardware error...

[QUOTE=thermalMan]So far, system is stable at 166Mhz. Seems all I needed was a CMOS wipe (Suggested by Asus tech). So far so good. However, Prime95 still gives me the hardware error...[/QUOTE]

How about your other BIOS settings? Is there any turbo mode, vlink or any other speed acceleration setting that you might have turned on?

One of the machines I'm running is a P4 2.6C on an Asrock motherboard. It was unstable, even at stock speeds, until I turned off V-Link in the bios (it was a VIA chipset). Not sure if your A7N has something similar.

I actually reset the CMOS. So I'm running with basically the default settings. The only thing I did was disable floppy, parallel and serial ports. And I changed the boot order.

So far, it's now stable. It seems Motherboard Monitor was causing some of my stability issues. However, I still can't run Prime95 on a 166Mhz FSB.