alrighty, so my computer isn't liking new games.

Processor: Intel® Core™2 Duo CPU E6550 @ 2.33GHz (2 CPUs), ~2.6GHz
Memory: 3070MB RAM DDR2 800
Hard Drive: 370 GB Total
Video Card: NVIDIA GeForce 8800 GTS
Monitor: Acer X192W
Sound Card: Logitech 5.1 70 Watt (High Definition Audio Device)
Speakers/Headphones: 5.1 Surround Sound Logitec
Keyboard: Logitech 250
Mouse: Razor Death Adder
Operating System: Windows Vista™ Ultimate (6.0, Build 6000) (6000.vista_gdr.071023-1545)
Motherboard: EVGA 650i Ultra
Computer Case: Antec Nine Hundred Series

i am thinking of doing the motherboard first to something like a 790i or x48 or something like that and building off of that in the next 3 months. but since i am clueless, i am going to the experts (you guys)

My humble opinion would be to grab yourself a e8400 or e8500 and a ATI 4870. What kind of power supply do you have? I'm sure it'll be fine though.

i have a rosewill 850watt psu, so you think my cpu and gpu are slowing me down?

Your CPU is a little slow, but it's on the same level as an 8800GTS really so there shouldn't be that much of a bottleneck caused by it.

Which games are suffering, and is it just bad fps, chug, etc.

far cry 2, fallout 3, crysis (still), stalker clear sky, and dead space. my fps is like 20-30 maybe in all of those and then everyone once in a while i get a nice wait while something loads.. med/low settings on them all is rather dull. my cpu is OCed to 2.66 and my gpu is @ 603mhz and memory is at 800, ram is also at 800.

would i need a new motherboard if i got any new hardware, i know pcie2 is backwards compatible but i wont get all that yummy speed.

Depends on the exact hardware but likely not. Is that 30FPS on high settings? If so it doesn't sound too off for some of those games with your hardware. I suggest a format and fresh install of Windows, latest drivers, etc. before going ahead and buying new hardware though.

this install of windows is only a month old, but ill redo it anyways, if that doesnt help much then i think i may have to start upgrading. is amd back and kicking yet? any cpu recommendations intel or otherwise?