Here's a review of the X-GamerZ ROM by LoLaTiOn from xda developers. This is by far the best gaming ROM I have ever seen for the Samsung Galaxy SL i9003.
This ROM has been specifically designed to play games, and by games I mean most HD games. I was successfully able to play, Frontline Commando, Real Racing 3, Subway Surfers, Temple Run2 and Vector without any lag whatsoever. The phone did not hang, it did not skip frames and there was no lag at all in all these games.
This ROM is based on Alpha 4 version of CM10 and has the same bugs as that of A4. Its a lean, clean ROM that offers you the best gaming experience this device can offer. Check out the video above for a visual display of how this device handles games that it was not designed to handle.