DDR2 800 or 1066?

Hi guys n gals

I need some advice on what RAM to buy for my setup.
Im not understanding RAM too well

My setup: E8500, ASUS P5Q Deluxe, 4850, 2gig RAM(to be replaced)

Now my MB - ASUS P5Q Deluxe supports up to 1066 DDR2.
I currently have 2gig Corsair XMS2 @ 800 and want to upgrade to 4GiG..

I have been looking at memory and found that the 1066 has higher Voltage and CL timing.. Does this make any difference at all to performance? Is higher voltage better or lower better, does it affect performance? etc
Will i notice any performance diff between the 800 and 1066 memory at all? Do i need to change any Voltage or timing setting if i get 1066 instead of 800 or is it set by the memory default?

Was looking at the 2x2048 gig kits of DDR2 1066mhz Corsair XMS2 or Kingstom HyperX.. those any good?

Thanks

Droogle

Im guessing that the extra performance will only be felt with a Quad core then?

Thanks for the advice!

ahhhh thanks for the reason! learn something new everyday..

btw im looking at the Kingston memory. Where i live its a little hard to find some of the other brands and its expensive.. but i think these will do fine!

http://www.newegg.com/Product/Prod [...] 6820134066

But why dont you buy one more 2 GB matching Corsair pair???

Lolz.. then its fine...