Well... the problem here is that I'm kind of between a rock and a hard place... the issue is that there's a problem that is not unique to nUI. It is impacting a LOT of mods out there ever since 3.0 and appears to be even worse in 3.1 -- I'm working to alleviate the problem as much as I can by reducing how much garbage nUI generates, but I don't know that I can truly fix it. Even very lightweight UIs are having FPS issues.
Given Bliz's new addon development policy, if I were a conspiracy theorist I would suggest it wasn't by accident. However, I do believe it to be just coincidence. The problem, however, is fixing it.
/sigh
This thread is a good example of the FPS issue in play for people who are using mods other than nUI...
http://forums.worldofwarcraft.com/th...03572404&sid=1