E6750 and Asus P5Kc mb, Fsb stuck at 266 mhz

[Scruff2]

Hello all, so i have a problem with my new rig, i cant seem to get the FSB to stay at 333.
It's always reverting back to 266 mhz after a period of time, my issue is not the multiplier or speedstep.
I only seem to be able to get it to run at 333 if i remove the MB cmos battery for afew minutes then once i put it back in the system runs at 333.
Yesterday i overclocked to 400 fsb, with ddr2 800 mhz ram running at 1:1, cpu at 3.2 ghz and it was very stable in intensive apps, problem is i put the computer to sleep, get up this morning and its back to 266 mhz .

Am i not clearing the cmos properly or does this motherboard set itself to 266 fsb for some other reason?
If i try to change bios settings while it's stuck at 266 fsb nothing changes upon reboot, it will only change if i remove the battery. I keep the cpu multiplier locked at 8, all speedstep crap turned off, 500w power supply.
I am using the latest bios.

If anyone could shed some light on this i would appreciate it, i dont want to lose my new rig for afew days so the shop can test it out, but i fear this MB might need to be replaced

Thanks alot

 

[akhilles]

Did you follow the manual to clear cmos?

 

[Scruff2]

heya, yes i have cleared the Cmos according to the manuals instructions, battery out, move jumper to pins 2+3 for 10 seconds, replace jumper to pins 1+2, replace battery.
This does not help, as soon as the computer is off for any length of time it reverts back to 266 FSB, when i check the bios settings they are all still set to my overclocked settings, seems it is ignoring the bios.

I have no idea what to try next
Anyone else with this problem found a permanent solution?

 

[akhilles]

Try another battery. It's not expensive. Let it in clear position for a few mins. Wait, did you remove the power cord & press the power button in the case a few times to discharge power in the capacitors in the psu?

Does the bios keep other info?