umm had a similar problem with my apps, wasnt the gc though, it was the threads, I lowed the priority of less important threads(as i was networking so i had a few)like listening thread as it was tcp, and only slept the main game server thread interval minus clocktime, then sent an update 2 the other threads 2 do there thang. and sleeped them for only (1) if they hadnt been updated, done wonders for performance dont know if its a good thing 2 do