X64 bit Win 7

I am planning to upgrade to window 7, but since I am installing a new OS, I thought I might as well go for x64 bit. I have checked all drivers and software to see whether they support it and they do. But currently I have only 3 GB of RAM.

I plan to add another 6GB = total 9Gb. I have a Core i7-920 machine, so I have 6 DIMMS. I originally bought Corsair dominator RAM (3GB=3x1Gb sticks), but the RAM is very expensive, so I was wondering whether it was compatible to use Corsair's XMS3 series, which is cheaper.

A friend recommended using Corsair dominator, but I never will overrclock it, so to me it seems bit of an uneccessary upgrade. Is their XMS series just as fast and reliable, at stock speeds? I also assume clock timings have to match, or something. I dont actually understand this much so I uploaded the images that CPU-Z tells me about my memory. Maybe you could explain. The memory I bought says 8-8-8-24 timings:

I think it was this: Click Here, but I bought it from a UK site. -> Here

Could someone explain in basic terms what these images tel me about my memory. Could you also possibly reccomend what to get (from Corsair). Thankyou

Images: