Will my AMD Athlon X2 4200+ choke an 8800GT if i get it? In other words, will my processor slow down my 8800GT? Therefor, show a decrease in performance.In games where your system is pushed to the limits, for example Crysis, and games that are CPU dependent, for example Supreme Commander, your CPU will bottleneck your graphics card.
The 8800GT is a FAIRLY high end card, whilst the 4200+ is a fairly low end CPU.Can i GIVE you a list of games and tell me if they will be bottlenecked?
-Bioshock
-CS: Source
-Battlefield 2
-Lost Planet
-Gears of War
-Call of Duty 4
-Company of Heroes

Which ones do i have to worry about, and which ones do i not have to worry so much about.
(These games i either already have, or i am thinkin about getting.)
I think you should be OK for those games, but you would EXPERIENCE better performance with a faster CPU.
Do you already have that Athlon, or are you thinking about buying it?yah, i got an Athlon 4200+, but my mobo has a the socket type AM2, so i can UPGRADE it easily if needed.I was going to advise you purchase a different CPU if possible.
As it is, save the CASH and buy a 775 motherboard and a Core 2 Duo CPU when you can, you'll definitely see the difference.i was acually thinking of getting a AMD Athlon 64 X2 5000+ Brisbane 2.6GHz Black edition because it overlcocks sooo well. People can easily overclock it to 3GHz and some even higher. This thing only costs $100. It is better than $200 core 2 duo'sTrue.
However, the ~£40 (I think around $80 maybe?) E2140 can be overclocked to an easy 3GHz too, and higher up models can go further for an even better performance boost.
In the end it's up to you, I agree that it is more cost effective to stick with the motherboard you have and just upgrade the CPU, however you will see better performance with a 775 mobo and C2D CPU.