Memory leak

[phone4me]

When i start up my game i it works fine, the prologue runs smooth except one thing, when i tab out of the game in any window mode it freezes for some seconds and that is really annoying.

I also have a memory leak problem, when i start the story the CPU bumps up to 90%+,if i play for around 10 minutes it crashes and tells me to close gta. The game loads very slow , i have msi GTX 970 4GB, i5 processor and i only use 2,5GB ram at the time.

i dont know what causes memory leak, I tried Vram and all that stuff, but it doesn't help!