Hahah. That was me. Bought the game around 6 days before it came out (keyword: 'bought'). Ripped the game to my hard drive (I have a jailbroken PS3) to save myself loading times, as well as not have to rely on a disk in general. I buy my games but my PS3 has a 1TB hard drive which I rip all my games on because I can back up games which I have bought (that is legal I believe, as it is my game and I own it) and don't have to take disks with me whenever I travel (which I do, a lot). Also don't have the trouble of switching disks whenever I want to play a different game.
Ross or I think BigAnt noticed the problem immediately, there was no trouble at all
and yeah, basically the match gameplay just stutters massively if the game is played off the HDD, not sure if that's an actual implementation put into place purposely or just happened to occur.. haha.