plz help me!!! Garrys mod freezing!!!

the thing is when i go on to garrys mod it loads fine, but if i go into singleplayer/multiplayer the screen freezes and every couple seconds the screen “blinks”. i have tried using a game booster, turning off the firewall, and changed my performance options to best performance, but it just keeps freezing… suggestion?

“game booster” wat

Post your system specs.

Gamebooster is a program that stops processes from running to free up ram. Pretty good if your computer is shit.
And. system specs please?

System specs please.