Actually i heard it the other way around, more pop in on the 360 while steady framerate on the ps3.(both will be identical houser already stated that)
"Grand Theft Auto IV is a digital masterpiece. Period. You will like the Xbox 360 version of this game. You will like the PS3 version of this game. Technically, they are the same! However, there are some minor variations."
The review states that their is a mandatory, 10 min install on GTAIV for the PS3, and an optional install on the 360. The review also comments that the 360 version runs a bit choppy, with pop ins and frame rate issues without the install, although hardly noticeable. here is there quote:
"When popping the disc into the PS3 for the first time, you’ll have a brief installation. Don’t worry, it only takes ten minutes or so, and there’s a pleasant bit of GTA history trivia to keep you occupied. So, unlike with Devil May Cry, you’ll be able to eat your sandwich prior to playing the game. On the 360, this installation is optional if you have a hard drive. I advise to proceed with installation—it reduces the already minimal frame rate issues on the 360. When the game finally begins, you’ll be treated to the best opening credit sequence I’ve seen for a game in a long, long time."
GRAPHICS
This is where things get interesting. We are sure that both versions of the game will be amazing, but the key points hit here are just enough push for us to say that even with a slew of DLC, the PS3 seems to be the better experience.
"The PS3 has a more relaxed color pallet, but this gives everything a more realistic look. If you don’t like the realistic look, and you have a HDMI connection, you can fiddle with your PS3 display settings and get it looking much more saturated. The textures are just as sharp as the 360 version, and there’s little to no pop-in or screen tearing. The PS3 takes longer to load than the 360, but I took several different head counts in game at different locations, and I always found the PS3 to be more populated than the 360. This could be attributed to the dynamic nature of the world, but it’s hard to tell. Either way, the difference was never more than five to seven pedestrians or three to four cars—it’s not really much of an advantage.
The 360 is bright. Boy is it bright. Based on discussion history, this one will be claimed to look better, but it’ll really be preference. The texture quality is the same on both systems, but the 360 has a more cartoon-like look. This isn’t a bad thing. It just depends on preference. I’d compare the difference to that of Oblivion on each system. The 360 also suffers from some frame rate drops that are almost non-existent on the PS3. Installing the 360 version on your system’s hard drive, however, will bring performance almost up to par with the PS3.