Q9550 suddenly throttling under load?

[Camberwell]

Rig is in sig, oc has been running without issue for over 18 months, and now suddenly under load the cpu is throttling back from multiplier 8.5 (max available) down to 6.

I have changed nothing in my rig, and all speedstep etc is (and always has been) disabled in the bios.

I have re-seated the cpu and cooler, and reapplied MX-2, but it still throttles.

Anyone got any ideas?

 

[Forceman]

What are the temps? 6 is the idle multiplier for that CPU, so have to wonder if it is throttling, or if something else is going on.

 

[flak-spammer]

You sure it's thermal throttling, and not C1E? On my CPU (Q6600) C1E drops the multiplier from 9 to 6. It should be a simple change in the BIOS.

 

[R-Type]

Yeah I would assume it simply isn't being fully loaded, if it is it could be a windows issue. Try turning windows to full performance in power settings to prevent throttling.

or maybe your pencil mod is wearing out

 

[Camberwell]

Thanks guys, but all of those things have been checked. C1E is disabled, Windows has always been at full performance, and I re-did the pencil mod. The hottest core (0) got up to 60C, CPU temp didn't even reach 50C before throttling.....

 

[Camberwell]

I've just noticed now that I'm back from work that the vcore is lower than before, even though it is still the same in the BIOS. It used to be 1.280V, now it's 1.272V (both idle). What would cause this? Is my mobo on it's way out?