When I right-clicked on a file in Windows Explorer it took an agonizing 8 seconds for the context menu to appear. I noticed that "Perforce" was in the context menu.
I tried to go to the control panel and modify the P4V installation to remove it, but windows whined about not being able to find a log file. No dice.
So I did the next best thing. I renamed the actual program from P4EXP.dll to something else in C:\Program Files\Perforce\P4EXP.
My context menu now appears in under a second.
I'll let you know if this causes downstream perforce weirdness, like files with two heads or three arms.