Massive frame drops looting or hovering mouse over inventory

I've tried to search for this issue with little to no avail. I've tried disabling hardware cursor, disabling all addons but no "solution" has worked for me yet. Basically what happens is anytime I loot a mob the game skips tons of frames, complete frame loss at times down to 0 and resuming once looting has finished. I can duplicate the behavior by hovering over anything in my inventory, even leaving the mouse on an item will keep my fps sub 15. Not sure what I can do to fix this but would appreciate help, thanks!

have you got the client from here? https://www.warmane.com/download

In that case, try with this client: http://forum.warmane.com/showthread.php?t=437071
it is 30 gb but you can reduce the size by deselecting the folders with other langauge packs (inside "Data")