Steam – Split Steam game between hard drives (Witcher 3)

pcsteamthe-witcher-3

I have a relatively old system and wish to install The Witcher 3 from Steam in my SSD drive in order to get load times down. However, my SSD (D:) has only 37GB total, and the game installation allegedly needs 38GB. I also heard that SSD's need about 10% free space in order to perform well.

So what I am willing to do is split the installation between my SSD and a larger SATA drive using symlinks. i.e.:

  1. Download and install the game in a Steam library in the SATA
  2. Copy most of the files to a Steam library in the SSD
  3. Make symlinks in the SSD pointing to some files in the SATA
  4. Edit the game's manifest file so Steam believes it is installed in the SSD (Boltclock's answer here)

So my questions are:

  1. Will this break some kind of Steam's or in-game checksums?
  2. What kind of files (or which specific files/folders if someone knows) are less frequently used and thus will have less impact on load times if i put them in the SATA drive?
  3. Do I have to keep some free space in the SSD for temporary files and the like?

Thanks in advance, and sorry if this is the wrong place to post it.

EDIT1: In this question, user Viper_Sb hints at something like this being possible, but it is not clear how.

EDIT2: Actually, the question mentioned in EDIT1 only deals with linking the whole game directory, not splitting it's parts.

Best Answer

It will work.

Steam is not going to get low level access to even figure out that you setup your symlinks to connect files together from different drives. It'll simply use standard OS calls to access those files, and it'll run without any issues.

I don't have any source, but if you created your symlinks properly, this is how they are supposed to work. If not, then there's a problem with the symlinks, not Steam.