Hardware decisions

Hey, any help would be appreciated. Thanks!

Straight to the point, basically I just upgraded to windows 7 (finally) on a new hard drive (cause iLike Xp) and now that I can actually utilize more ram I have a dilema. (for decision making purposes the computer will mostly be used to game BF3) currently I am running 4gb of 1066mhz ddr2, reduced timing mushkin ram. Then ram is actually really good. But I do also have two other sets of ram. (all 3 sets are 2 x 2gb) but the other 2 sets are ddr2 800mhz. My question is if i would be better off with more of the slower frequency ram? (unfortunately the other 2 sets timings do not match up...) Also which would be better for when i overclock my cpu again?

System:
Q6600, gonna oc to probably 2.8 or 3.0
cnps10x xtreme cpu cooler
p5q-e mobo
antec 1200 case,
gtx 570 oc to 815 / 2000 very stable
a raptor 150gb WD 10krpm HDD
auzentech x-plosion sound card.

I guess I should let you know how its performing at the moment...
the core temps vary from 54-67 celcius while under load (BF3). (cooler always maxed) My CPU monitor usually shows 70% utilization,
my GPU temp maxes at 54 celcius, never goes any higher, while gaming BF3 99% utilization.
my room temp always goes way up when my computer is running, its probably around 25-30 celcius ambient (and i live in canada... lol)

*edit* sorry, I forgot to mention my fps almost never drops below 45 with a max (with vsync) of 60 and my resolution is only 1920x1080

anyways, if you need any more information for an informed decision I'll be glad to post it. Thanks for your help!
-(I'm at work right now, but I will post specifically what the ram is when I get home.)

proc now overclocked to 3.0 ghz, runs stable. But I also have another question: even with the overclock the temps seem really high, could anyone tell me what the temps should be when oc'd to 3ghz?

Those aren't terrible temps at all.

I really wouldn't worry about it unless it isn't stable.

RAM, it depends on what you're doing. 4GB is still a high amount of RAM. You need to try it out and see if it makes a difference for you.

Welcome.

Thanks for the welcome! got everything figured out mostly however there are some minor changes... mainly now my temp spikes at 98C on my cpu,(in S & M) its running at 3.4Ghz with a 1.35 voltage... or it might be 1.3 sorry its late and my monitoring systems arent the most accurate. I also voltage tweaked my gtx570 and the clocks are at 1700 shader, 850 core and 2100 mem now. Also got a non public released version of my bios from evga, I can now crank the fan speed to 100% Everything is stable, but I am still getting some lag when I scope in and out in Battlefield3. I also noticed from the changes I made that my FSB:RAM clock ratio is 2:3 now... I was shooting for 3:2 so a little bit of a failure there... Do you know if that will affect my performance? And if so, how I would go about changing it short of underclocking my ram? Or would that be the best solution? cpu (378 x 9) DDR clock is 567 with 5-5-5-15 timings. Forgot to add before that my ram is OCZ reaper edition 1066 2x2gb