[Damien_Azreal]

GTAV isn't really a good game to "test" a new PC with.
The game is amazingly optimized and not demanding in the least. Of course you're going to get great frame rates and solid performance.

If you want to test your PC, you're going to need to really use some more demanding games... which means going to some older titles.
As funny as it is, Crysis (yes, from 2007) is still one of the better games to test a new system with. The sequels are far more optimized, but the first one can be pretty resource heavy.