Saints Row 2 isn't a GTA killer, but it's a GTA alternative. It's tough not to hate on the slightly lacking production values, but when you see the rest of the game it actually makes a bit more sense. The technical shortcomings are the only truly bad part of Saints Row 2, and, sadly for PC gamers, it pretty much kills their experience unless they can play with the bulk of the visual settings turned down or off. Not doing so ruins your gameplay experience. There's enough crazy-insane tomfoolery to keep a machete in the hands of even the most straight-laced citizens, you'll just need a super-computer to even think about running it.
I had an old e-machine and tried playing Saint's Row 2 not too long ago, and it was a no go. Some of the worst stuttering I've seen, and I once saw John the stutterer (Howard Stern reference).
My system had a 1st or 2nd gen dual core AMD, I think somewhere around 2ghz clock, with 1.5gb of RAM, and a cheap 256 or 512mb nvidia graphics card. Sorry I don't have my exact specs... your system sounds a bit better, and with the Intel processor, you might have better results. Good luck!