I have 2 HDD's They have the same capacity of 465 GB, can I transfer everything into the other HDD?
If its Steam the use the built in library feature.
If its not ...
1) Open the games install folder
2) Copy the entire install folder to another location on your PC (not the final destination folder)
3) Uninstall GTA V & RGSC (keep your configs and saves)
4) Reinstall RGSC and GTA V making sure to change the game install location to the new drive (its OK if RGSC is still on your C drive)
5) Run RGSC, log in and let the game start to download
6) Quit the launcher
7) Copy the existing install folder over the new install folder
8) Run the launcher, it will verify existing files then launch the game
Still if you have the physical version with cd or a fast internet connection just re install it is always safer.
If the second hdd you have is still 5400rpm and not new you still maybe face problems and will have huge loading time in this game.