Why it's lagging?

GTX Boy

Commendable
Apr 17, 2016
3
0
1,510
Hello,guys.I have this configuration and it lag sometimes in GTA V.Will new graphics card solve it?Thinking about GTX 750Ti 2GB my specs are down below.
4GB RAM,
AMD Phenom II X4 925 @ 3.1 GHz,
HD 6670 1GB DDR5.
Also I can take phenom II X6 1045t very cheap is it worth it?Can with this upgrade my system play GTA V on high?Thanks for the answers.