Last year when I got the 680i, I bought 2x1024 gb corsair ddr2 1066 c5d 8500. I decided to upgrade with 2 more 1 gb sticks. The original pair were v 2.1 i think (from memory). The next 2 (which i got yesterday) was version 4.1 or 4. something. Could this cause a prob. and if it could, how can one upgrade down the road if versions can't be mixed?