Friezes in many games

Hello, faced such problem. Bought a computer, when you purchase the tests in GTA 5. Everything was perfect on high graphics settings, while shooting, sharp turns and explosions of the Frisians had not been made or if there was something completely invisible. When checking the performance in the game showed around 40-50 FPS.
Reinstalling Windows, installed Steam version of GTA 5, went in and the chaos began. All frieze to play, stupid slide show, set minimum settings in game and via the file - all as friezes, sly show, especially if you start to go fast.
Downloaded Assassin's Creed Unity, Watch Dogs 2 - at the minimum setting the slide show.
On minimum settings, played in the Metal Gear Solid 5 The Phantom Pain - FPS stable 50-60 frames.
Played Dying Light on minimum settings possible to play, but there are sagging and joists.
Played Sims 4 on minimum settings with 200 FPS when playing 40-50 + frequent friezes and podragivanija.
The Long Dark - on minimum settings 30-40 FPS playable
Far Cry 4 - on minimum 30-40 FPS to play, but sometimes frieze
Raft - on the average or above average and frieze hangs sometimes
The Forest at top speed played well, sometimes there are friezes
PC Building Simulator - the minimum salary, is played well, sometimes frieze
The funny thing is that my other comp is a little different from mine, it even worse, but when playing the same GTA 5 is all on minimal, and sometimes even on medium.

Perfomance of my PC:
Processor:Intel® Core 2 Quad Q9400 (6MB cache, 2.66 GHz)
Video card:Gigabyte GeForce GTX 660 2gb
RAM: 4gb
Hard drive: SEAGATE 250gb
Power supply: ~450W (Honestly don't remember how much)

Har-Ki PC friend:
Processor: Intel® Xeon® X3323 (6MB cache, 2.5 GHz)
Video card:Gigabyte GeForce GTX 750 1gb
RAM: 4gb
Hard drive: 1tb
Power supply: ~450W

What to do? How to be?