SPCR

I've got DDR2 Corsair Dominator 2x2gb at a rated 8500.
I bought another set but it turned out to be 2 x 1gb instead of 2x2. I haven't received it yet.
My question, will I see better performance even though the sticks are different?
or should I try to sell it and search for a 2x2 set

Not sure I understand the question as posed. So let me answer some others and add more questions

Are you running out of RAM for some apps? Do you have apps that need more RAM than you've got in place? Do you have a 64-bit OS (32-bit Windows cannot utilize more than what you've got in place)

If all the RAM is specced the same and merely different sized, then you can place the 2 x 2GB in one set of dual channel slots and the 2 x 1GB sets in the other.

CA_Steve wrote:Not sure I understand the question as posed. So let me answer some others and add more questions

I use a ton of tabs in Chrome so it pretty much uses up all of the ram.
I currently have Win8 64bit. Its showing 3.5/4 gb being used. All I have open is Chrome, Windows expolor, some hardware monitoring CPUID, and foxit pdf.

All of the ram will be the same, 1066mhz 5-5-5-15. Its not running at that atm cuz my mobo auto set it to 667 5-6-6-15, but I'll change that shortly.

I don't quite understand the channel system so that's why i wast sure if it made sense putting in the additional sticks of a different size.

Let's say your mobo calls the dual channel sets A and B. As long as the RAM in slots 1 and 2 for A are the same size and the RAM in slots 1 and 2 for B are the same, then you'll see all the memory addressed. If you mix them up, generally the BIOS only addresses the lesser value. So, if you see 6GB at boot, then it's in the right slots. If you see 4GB, then you effed up

I don't know anything about Win8...but....are you sure it's actually using all of that memory or is it allocating a large portion of it for cache/page file, etc...

As an example, I've got 4GB and Win7. I've got 11 tabs going in Firefox. 1 is this one, 10 are google.com/news. It's only using 377MB.

Im not sure how its being used. The attached shows what i see

Yep - high RAM use. Seems odd. For grins, have you tried opening up the same tabs in another browser for comparison?