I3-3220 + hd7870 oc

Your CPU is more then likely holding you back yes. It's clock speed firstly and the fact that its a dual core processor as well are what keeping you back from higher frames with your current card yes. Stepping up to a i5 3570k would yield significant frame increase as well as perhaps the cheaper i5 3470. You have a mid level card which is almost a high end card you will need more cpu power to bolster your card as well as a suggested 8 gigabytes of ram.

is that so..can i overclock my cpu? so that it can support with gpu

No you cannot overclock

Please tell your cpu usage while playing that game in taskmanager

hitman absolution is a CPU dependant game, though that i3 ought not be holding you back by much - its as good as any AMD chip in the game.

maybe take a read on this:
Hitman: Absolution GPU/CPU Performance Review

i am not saying that an i5 would not be better but with your set up you should be getting better, what drivers/settings do you use?

i just checked..my cpu usage up to 70%....and when i played the game during cinematic scene like open door..sometimes it will lag and then fast forward for 10 sec..

looniam:waht driver do you mean?

got the latest/greatest?
http://support.amd.com/us/gpudownload/windows/Pages/rad...

try lowering your resolution/settings to see if you get an increase in FPS. what resolution are you playing now?

He mean to say download latest amd graphic drivers and install.well cpu at 70% means that it is not bottlenecking.go to game settings and try to set vsync - off.

now on amd 12.11 beta driver..i played on 1920x1080..i dont want to lower down the res..i will try off the vsync

Did you face lag in every game?

ive tried..the fps still same..

nope..just in hitman...or maybe the game itself problem?....

ok..i have re-checked the cpu usage..sometimes its hit to 83%..so maybe as you said my cpu do bottleneck with my gpu...then i just got 20fps in average...

Best answer selected by onelah.