low fps in games after a thunderstrike??

During thunderstorm recently, one lightning strike happened to hit our apartment. I did not have surge protector for my desktop. My psu was destroyed, changed it. Now the pc boots up everything seems okay. But the games i play before now are unable to run smoothly. Could the lightning have caused any partial damage to the internal components?? Is there any way to verify if the gpu is performing optimally??

Phenom II x6 1055t @2.8ghz
8GB Ram DDR3
Radeon 6770 1GB GDDR5
Gigabyte AM3 socket Motherboard (dont remember the model number)