Remmi2002

If you use an anti-virus programm, make sure to exclude GTA V directory and the folder you store your mods in from surveillance.
 
Then try a clean reinstall, and maybe even try to turn the realtime-protection off. AV can cause huge problems with RPH.

Hey guys,

I don't know how many of you know about Large Address Aware - it's an application thanks to which programs can use more than 2 gigs of memory on x64 systems. Quote from original topic on techpowerup.com:

So, how does this apply to GTA IV, you ask?

Wonderfully!

After applying the LAA flag to GTAIV.exe, my game is much more stable. It might be just a placebo effect, but it feel smoother, textures pop up faster and it crashes less (from 15 mins. to about 30 - 45).

Link to the application and instructions how to use it are here - http://www.techpowerup.com/forums/showthread.php?t=112556.

It also works with other games!

Just remember, you must have x64 Windows to use it.

Try it out and let me know if it worked for you!