Why in Edit/Preferences/ Memory can't I switch between Memory and Performance?

[Billy27735954cpio]

I have been having issues with the preview being choppy. I have tried everything that I can find info about nothing seems to help at all.  At this point the only thing I think I haven't tried is to change between Memory and  Performance in Preferences. The problem I'm having is there are no option to do that. Any suggestions why this might be? 

[Ann Bens · Accepted solution]

This option is for optimizing rendering and does not excist in the newer versions anymore.