Hi, I just upgraded my CPU to an XP 3200+ Barton core from and XP 1800+. My ASUS A7N8X mobo didn't recognise it automatically so I tried to change the BIOS settings. I changed the external frequency to 200MHz and the multiplier to 11x (as what I thought it should be) and it won't reboot. It just hangs and I think the graphics card also packs in (the fan has LEDs which go out after restarting with this config). I also changed the memory settings from "auto" to "by SPD" which bumped it up to 200MHz from 166. I can get the multiplier up to 12.5x on 166MHz but as soon as I change it again it hangs and I have to flash the BIOS. Current settings (according to CPU-Z): CPU core voltage: 1.648 v core speed: 2079.5MHz (12.5x) 266FSB memory frequency: 166MHz Specs: Athlon XP 3200+ Barton core ASUS AN8X deluxe mobo 2x 512MB Corsair ValueSelect PC3200 RAM 128MB GeForce FX5950 graphics Vantec 470W PSU Thanks for any help Just read the A7N8X thread so went back to check a few things - mobo was revision 1001 but I updated it ages ago to 1007. FSB spread spectrum was set to 0.50% so turned that off, set the freq. and mult. settings and it booted to the POST screen showing an XP 3200+ with 1GB RAM (also moved one of the sticks into the second channel) but hangs after the memory test.