Reshaper is known to be quite slow, slowing down VS by a lot, how much depends on the project. Besides, newer versions of VS and its refactoring features have come a long way, for me, it has made Resharper obsolete.
Having switched from VS to JetBrains Rider a few months ago, I cannot recommend it enough. Way faster and less clunky than VS without Resharper, especially if you're targeting Unity. They're so far ahead I simply don't see any way for Microsoft to catch up any time soon.
https://resharper-support.jetbrains.com/hc/en-us/articles/20...