Access to VRChat temp files is the major cause behind VRchat's slow performance. Clear VRChat temp files by visiting C drive, then click on Users, and then click on your username through which you are signed in. Search and click on Appdata > Local > Temp. Now look for the VRChat folder and delete it. Close all the other apps running in the background. Open task manager and close all those applications that you are currently not using. Hopefully, this will work and fix VRChat's slow working or loading issues.