Your whole system is the problem.I use an i3 3240. It only supports VGA 2.0, but my VGA is 3.0. Is the problem because of my CPU?
my spec pc are:
PSU 420+ bronze
MOBO: B75M - HD3
RAM: 2x4 1333Mhz
CPU: i3-3240
VGA: R7 260X
oh I understand thanks for the answerBy VGA 2.0 I think you mean PCIe Gen 2 (?)
Yes, its your CPU that's bottlenecking the performance of the GPU (VGA, as you call it), to PCIe Gen 2 speeds.
That being said, lagging is not just the cause of your CPU, but your GPU is not that powerful either. Even if you put it in a system with a better CPU, it wont make things "lag-free".