HOWTO: Overclock an Athlon 3800 X2 on Asus AN8 Premium
Just wanted to post up and say that i've got a perfectly stable overclock dual core now _very easily_ and my bios settings to do so (which has confused me for a while!).
Set clock speed to 240mhz
Set cpu multiplier to x10
Set HT multiplier to x4 (Note: make sure it's not x5!)
Set Max Ram clock to DDR333
Lock PCI bus at 33mhz
Set CPU voltage to 1.3375v
This gives you 2400mhz (2.4ghz) with the RAM running at a nice even 400mhz (because the DDR 333 setting is actually the RAM divider, not the RAM clock speed) and the HT bus at ~960mhz (nicely under the 1000mhz limit). Of course with faster RAM you could up the divider and run the RAM at even speeds but i find 2 gig of RAM better than 1 gig of the fast stuff. My RAM timings are stock BTW (2.5-3-3-6) with CT2 as CT1 isn't stable on this motherboard with this much RAM.
Keep the HT under 1000mhz as this will make the system unstable (I booted up with the HT multiplier at x5 and all _seemed_ ok till i started a game and it locked up quickly).
I'm pretty happy with this overclock as only the CPU is actually being overclocked, everything else is stock, and i've not had to alter voltages radically. Over the hot weeked i saw CPU temps hit a max of 52C whilst gaming on my twin-rad asetek system which is cooling the chipset, CPU, and GPU - the GPU hit a max of 35C (damn these 7800's run a _lot_ cooler than the 6800s!). I'm sure i could hit more but with 2.4GHZ on both cores it seems pretty quick to me :)
BTW one oddity - if i ran asus's overclock util on the desktop hitting the 'X' to close the app caused the machine to instantly reboot(!) but it's totally stable in games, passes memtest etc etc.. I guess it's because the tool is doing something dodgy with the hardware, no loss.
