Move temp folder off OS drive.
Create a new folder on E:
Point temp audio directory in RB to there.

I have programs and VST'(i)s on C drive. That doesn't seem to be an issue. They run in Windows area of C: anyway when envoked (I think). OS usually uses a C: temp area to run things, and RB gives you a chance to separate the audio temp from the system temp.

Mind you, when you shut down RB the audio temp folder gets cleaned out, so it will be empty except when working in RB. But when you make edits or record, those needed chunks of data are in the temp audio folder until you save and close. Then they get written to the file and the temp area gets cleaned up when you close.

I do not work here, but the benefits are still awesome
Make your sound your own!