Just this morning Gran Turismo 5 just out of nowhere started loading really slowly.
I fixed this by signing out of PSN. It’s not ideal if you want to play online, but it’s worked for me.
It should be noted that the problem can been seen from the XMB before you even launch the game – just after it displays the message that you’ve “signed in”, watch the clock and see how long it spins; this is the console synchronizing the time with PSN. If this takes more than a couple of seconds, there might be a problem.
In addition, check your friends list. If it seems significantly shorter, and each friend is only very slowly appearing one at once, you can count on having troubles launching GT5.
Finally, note that when you launch GT5 without being connected, the points where the game hangs are the points it asks you if you want to connect to PSN.
I can only assume that this is a PSN issue because I can confirm on my Tomato router that my connection is entirely utilised. Of course, that doesn’t guarantee the problem isn’t my end…
If your loading problem isn’t thanks to PSN or a slow internet connection, then it might be that it isn’t installed, the HDD is dying, the disc is scratched, the Blu-ray is dying… All the usual suspects really.
Good luck!