How much of a bottleneck is my CPU?

[litex]

Here are my system specs:

Gateway dx4200-09

OS: Vista home premium (64 bit)
Mobo: Systemboard with AMD 780G Chipset
PSU: BFG 550W with quad +12v rails (20A each).
CPU:AMD Phenom X4 9100e (1.8Ghz)
RAM:4096MB 800MHz Dual Channel DDR2 SDRAM (2-2048MB modules)
HD: 640GB 7200rpm Serial ATA II/300
GPU: Diamond Radeon hd4770

Right now im shopping around for a new monitor in the 23" range, so I'll probably be gaming at around 1920 x 1080 if I go that route. Obviously my slow CPU will bottleneck my GPU, but will it be obvious at this resolutioin? I don't play any particularly demanding games, mostly rfactor and every once in a while CoDWaW.

So, is a 23" monitor a good idea or should I look for a slightly smaller one?

Thanks

 

[Bluescreendeath]

Overclock your CPU.

Since most games only use 1-2 cores, your CPU is basically a 1.8GHz AMDx2

But your GPU is a 4770, so your bottleneck won't be huge. If you want to Xfire another, then you'll have to overclock your CPU