Even on my new PC i got for christmas, FF13 and FF13-2 should be playing at 60fps but i'm at 30 and sometimes i drop to 20 for no reason and my new pc is more than enough to handle the games flawlessly.
Processor AMD A10-7700K Radeon R7, 10 Compute Cores 4C+6G
Speed 3.5 GHz
Number of Cores 4
Video Card AMD Radeon HD 7850 2gb
Memory 16 GB
Operating System Microsoft Windows 7 Home Premium Edition Service Pack 1 (build 7601), 64-bit