Different results on both MSi Gtx 680 Twin Frozr

Hi all. I just bought 2 x Msi Gtx 680 Twin Frozr, and i tested single card on 3dmark 11.
On first card i have more different variations fps between tests. And on second card i have smaller variations fps between tests.
I run few times 3dmark 11 on both cards. It is normal or not? Why on first card i have more different variations on fps between the same GT tests?


1 card:




























And now second card ( look closely at variations in fps between the same GT tests, they are just smaller ):
















RMA that first card? Or what now?


Why i on first card i have more fps variations between the same GT on next loops? For example: 9458 to 9399 and 9438 to 9396 scores.

I mean card is working properly?