Low FPS

Hi, in my opinion i have a good PC for CS:GO, but i have low FPS, i have 80 FPS in main menu, 100-150 in loading, and 30 in game.

I have 4GB ram
Dual core E5700 3 ghz
GEforce GT 520

Is this normal?
What is the normal FPS for this spec?
What can i do to ncrese my FPS?

I googled, same fps

1. Your fps seems pretty accurate for your specs in my opinion
2.^
3.Set all settings on low if you already haven't done so already or go buy a better computer(CSGO is cpu heavy)
4. Sorry, you don't have a good pc for csgo