That's when it shuts down to one core, usually a driver or game issue to which ati are doing a grand job of sorting out.
Plus a lot of sites have to be taken with a pinch of salt, like toms hardware which are known for being nvidia fanboys so would use old drivers and cherrypick tests that favour the nv cards for example.
And to further add to things the 9800gx2 is now delayed to march because of driver issues and atm scores 14k in 3d mark 06, the x2 manages about 18/19k.
VR-Zone : Technology Beats - GeForce 9800 GX2 Launch Delayed Till 18th March
Im not an ati fanboy as my last 2 cards were nvidia, you won't believe how many people have brand loyalty despite clearly getting pwnt.
hd4870x2 is out in 2/3 months which will be double the gpu's of the 3870x2.
So it's certainly a bumper crop of cards this year, shame nvidias are only g92 revisions.