Some of the game install on the PS3 are crazy.
I am cleaning my old PS3 before giving it to my stepdaughter and it took a whole frigging 15 minutes to delete GT5 and Resistance 3 delete has been going for 10 minutes ....
By comparison, deleting the 3G of Borderlands was 10 seconds...
I think it has to do with the number of files, what we see as a game name is actually a folder on the PS3 and some games have thousands of files installed instead of one big file and like Windows, the PS3 takes forever to process folder with huge amount of files...