Radeon 4770 issues

So I just brought a new video card Sapphire Radeon 4770, did a fresh full format before installing first with windows xp, specs are:

Intel Dual Core 2.0 Ghz
PSU 500W
Windows XP
Widescreen 1280x720
RAM 2GB DDR2
Sapphire Radeon 4770

I updated the card drivers, using catalyst 9.9 , I'm using it to play Aion, regardless if it's on very low on very high, framerate flows btw 12-17 FPS, funny enough at times jumps at 100 fps and keeps at 60-70 fps, I brought it to change a Geforce 8500 Nvidia Foxconn and I have to say it's not much of a improvement? am I missing something on the config? already sent it for RMA and this is a new replacement.

What FPS did you get with Geforce 8500?

You are being held back by your CPU, it's not fast enough for that card. If you increase your resolutions and still get same FPS = CPU bottleneck. I've been contemplating alot myself whether I should go with a 4670 or a 4770 due to this reason also, as my 4800+ is quite outdated. That's why you don't get the full potential of a card's performance.