Why do my games lag when my computer is good?

biggerknocks

Reputable
Apr 16, 2015
10
0
4,520
I have a good computer: Processor Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz, 3801 Mhz, 4 Core(s), 4 Logical , 16 GB of ram, AMD Radeon HD 7900 series. But my games lag unless I go to medium or low settings but my friend says for most games I should be maxed or near maxed graphics. Is my friend right or do I need an upgrade to play games better.