Monitor upgrade - how much of a performance drop?

[Podmonkey]

Ok, im currently running a 19" 12:10 ratio monitor. Planning on upgrading to a 22" with a ratio of around 16:10 or 19:10 (dependant on the rest of the monitors stats and if the top 1 will gimp me too much). I am just curious as to exactly how much in a drop in framrates I will see? the picture might look lovely when im not moving but thats useless if my frames are screwed on the move.
Any help would be appreciated. Cheers.

Oh my specs are as follows:
Cpu: Athlon II x3 435 (@3.5ghz and 4th core unlocked)
Gpu: Inno3d GTX460 768mb
Ram: 4gb Kingston 1066
Im guessing the rest dont really matter that much for this.

 

[Yakyb]

on what game?

 

[Podmonkey]

Games I play are currently Mass Effect, MW2 and a bit of WoW. have them all maxed at the mo. Playing the Mafia2 Demo, everything on max except physX with average fps of 53, and MW2 online never goes below the 90fps cap for more than a second. Mafia2, Witcher 2 and crysis 2 are games im looking too in the future.

I know ive not got a chance at maxing it but id just like to know how much of a drop in frames im going to be looking at? 10? 15? I know its most likely not that simple but im hoping someone who has done a similar upgrade can shed some light on it.