PS3 freezes in game and psn menu for a couple of seconds

My ps3 is a slim 250BG I cleaned it restart system everything. Now the problem is my ps3 freezes for a couple of seconds and resumes fine in game and menu sometimes I would play zombies and it freezes 20 seconds later I find myself dead . I'm on psn menu and I'm scrolling looking at my friends it just stop for a couple of seconds and resumes.

I even tried playing digital and it still happens I would play watch dogs and the characters would glitch during video play and when I'm driving the music will stop playing like if it's buffering although when I play it's fine runs smooth I kill people easily fine and then one day it just froze completely while playing when I exploded a lot of grenades in watch dogs

Reformatting may fix it, but the chances are extremely low. It's most likely a hardware problem. If your system is still under warranty, then you should get in touch with Sony to service/replace it for free. If it's not under warranty, you can still get in touch with Sony to get it serviced/replaced at a price, or consider getting a new PS3.

I had a similar problem with an old 320gb Slim over a year ago, but it was still under warranty. I sent it to Sony Australia, they prepaid the shipping cost and sent me a replacement within a few days.

Good luck.