SLi screen tearing

[Pob255]

My 9800gtx sli has been fine for a while, untill last weekend.
I hadn't actually played any games recently, however now I'm getting screen tearing on any game I play, also on 3dmark05

I updated my drives just to check, 257.21 WHQL, still there.
I removed the drivers and rivatuner just incase, rebooted into safe mode, ran driver cleaner to fully remove all traces.
Rebooted and reinstalled 257.21, still there
Moved my sli bridge to the other connectors, still there
Reinstalled rivatuner, underclocked both cards and changed the fan speed to fixed 100% (my they are loud) still there
Tried monitor via a d-sub cable and DVI to d-sub adaptor, still there

Just bought a new sli bridge off fleabay just incase but I'm stump out of ideas.

Happens on any sli mode, normal or ether of the 2 alternate frame render modes
Ether card on it's own works fine, Force Vsync on and I get less tearing but still bad enough to make games unplayable.

[kalniel]

Not sure if it'll help, but you could try resetting your BIOS CMOS incase something funky is going on with PCI-E lane allocations.

[Pob255]

Well an update on this, I booted into my my old windows7 beta and apart from it complaining about it not being a beat and so not activated or valid, sli is as smooth as slik, not the slightest issue with 182.57 drives

I got my new sli bridge, a hard one, installed that not change in win7beta still smooth still tearing so much it's unusable in xp

I can only conclude it's shoddy xp drivers