Let's start with info about GTA 5 performance.
GTA 5 is really CPU and RAM hungry, many people believe it's not optimized at all, it's not reacting to PC upgrades as much as other games, it can load 4-core CPU to 100% and require more, it can allocate 12GB ram easily, but we still love it and want big and stable FPS, so let's try to get it.

The 2 main reasons of stuttering is: data loading and background CPU usage.

1. buy more RAM
2. optimize your pagefile
   1. if you have SSD - configure pagefile only on SSD
   2. if you have only HDD - configure pagefile with fixed size and move it to beginning of disk
3. defragment and sort your data
4. disable shader cache

1. increase game process priority
2. shut down as much background processess as possible

Let's talk about each trick.

Seriously, this game can commit 12GB of memory for it needs, so easiest way is to fill your PC with an additional RAM. The more RAM you have - the better your game experience is. Start with 16GB, but if you can afford more - buy more. Windows will precache all free memory with data it read frequently, basically preload your game data.

So what pagefile is? It's a file on your disk that's using as 'backup' memory. In cases when you running out of memory - rarely used memory pages (memory page is fixed amount of data, storage unit) thrashing (moving) to this file. It's originally designed to 'do not instant reboot your PC when you have 0 bytes of free memory and you need to allocate more'. Generally you want to avoid using this file, because it really slow down your memory usage speed. Just imagine - RAM speed is on thousands level and your HDD is on decades level, no doubt it provides lags.

1. it can be fragmented
2. it can be not in the beginning of your HDD

Your pagefile can be fragmented, in other words it can be splitted and allocated in different areas of your HDD. HDD in fact is bunch of magnetic discs rotating at very high speeds (7200 RPM usually) and by it nature data allocated near beginning (center) of disc can be read at higher rates. So you want your pagefile to be defragmented (as a single series of data) and closer to beginning.
Non-fixed size of pagefile makes it fragmented, because when it changing it size - it allocates currently free zone of your disk, and it can be not near already allocated zones for your pagefile.
In order to prevent this you need to set up your pagefile as fixed size, defragment your disk and move pagefile to beginning of disk.

Structure:
- general info about gta performance, ram consumption and cpu hunger
- the reason of stutters, content loading and disk usage
- ssd as pagefile
- hdd defragmentation, data zoning
- ahci mode
- shader caching
- gpu overclocking, occt for error checking