>>347132423
when your pc runs out of RAM, it starts using the disk as backup RAM instead. on linux it's called "swap partition", on windows it's called "pagefile".
vrchat tends to use a lot of RAM and have RAM spikes, so it often goes into pagefile.
your pagefile is going to be stored on C drive where windows is installed, and the less free space you have, the smaller the pagefile will be, and then windows will have to clean up and re-fill it more often with data that should've been in the RAM. so basically you'll have worse catching optimization and worse performance.

this is only relevant if your RAM usage is high. so people with 8/16GB of RAM will feel this a lot more compared to people with 32/64GB of RAM.