Actually, the game isn't looking for multiplayer servers or anything like that.
Before Something Awful picked up on it someone in the official Playstation forums actually found that the game is sending packets to the Social Club. Ever notice sometimes when you plug in your PS3 and your internet isn't hooked to it that sometimes it will still be trying to "log in"?
Well, because of this system quirk the game is also trying to send information to the Social club (you know, so that your single player times and achievements will be seen on the internet) but the game nor the system seems to be able to distinguish the fact that nothing is getting through.
SO! what its doing is slamming the cache over and over again with attempted website searches and then eventually fills up, locks down, and the whole thing goes "splat".
The user on the Playstation forums also noted that whenever the Social Club is down and unavailable that it will cause major freezing as well.
He managed to find this out using the Linux OS and tracking the packets and seeing what was being pinged every two minutes.
So, its not really multiplayer....it's the social club