M17X Windows 7 - huge difference in GPU temps!

I wonder if anyone encountered this issue yet.
Performed a fresh windows 7 install, updates, drivers from Dell.
Everything seems to be perfect (same sound stuttering, same DPC spikes ). But 4-5hrs after the installation I noticed a 10-13c difference between the 280s (9400 disabled, SLI enabled, Physx disabled) when idle, the fans kick a notch, not the full blast and the temps stay 50c/40c stable. So one card is always 50c with the fans half speed on.
Tried some stress testing/gaming and got surprised - max as well as load temps are equal - no difference.
But as soon as I return to idle - one card goes to 50c and stays there.
What's the catch?

 

Ok. Did a run with OCCT GPU memtest got zounds of errors.
Opened the system reseated the GPUs, SLI cable, cleaned the fans... Turned it on, first few mins both temps are equal 40c, run OCCT again - 0 errors, during the run temps got to 50ish, fans kicked in, one card got back to 40c the other stayed at 50c. Did another run with OCCT - zounds of errors!
Any ideas?

 

Ok. This is my primary 280 card that heats up. Now if I stay Idle after boot and the temps never rise to 50c - everything is fine. But as soon as they hit 50c, the primary card never goes below 50c. Load and Max temps in games stay the same.
two screenshots; 1 during Crysis, 2 - idle.
Would appreciate some feedback.
Thanks.

 

Yep, it's a driver issue. I should have checked the proper thread before posting. Looks like one of the cards (both at times) do not downclock themselves after gaming/stress tests....
And that's Dell' official driver....

 

Which Dell driver is not DCing properly in W7? (I've lost track - lol)

 

the current one : 186.64

 

Installed 195.81. All is fine now. The the GPUs still boost when browsing but it's minor and probably more W7 related issue.
End of story....for now (crossing fingers)