Oh you're playing on the Lamebox? Sorry to hear that.
Um GTA IV runs and looks better on the X360 than it does on the PS3.
Well guess what GTA V is being developed for PS3 this time! Also after playing IV on both consoles they run about that same. If there is any difference it must be tiny and unnoticeable.
I have both versions too. I wouldn't say the difference was outrageously drastic, but I wouldn't say it was "tiny and unnoticeable" either. I noticed the difference immediately. The 360 version had more dithering, but the PS3 version was just muddier, and the lighting was far less dynamic. e.g. sunrise and sunset looked nice and natural on 360... on PS3 it looked like someone sprayed orange juice everywhere. Characters clearly had less polys, it was most obvious on their faces. The framerate was less consistent.
For the first few years of this gen, it was very common for the PS3 versions to be worse. Why? Because, the Xbox is essentially just a PC in a console casing. Whereas the Playstation is Sony's proprietary technology that they design from the ground up. Every time a new Playstation comes out, it's like the first day of school for the developers. The good news is that this far into this very long generation, the devs have the PS3 licked. The PS3 version of GTA V should be much, much bettter than IV was.
Caution - You are approaching the periphery shield of Vortex Four