Occasionally when I warp to Seyda Neen, there is a cliff racer Somewhere on the map and it causes my fps to drop to less than 1. What I have to do is keep turning until I can find it, then kill the cliff racer through a console command.
This has happened several times now and I'm sure I'm not the only one.
This Only occurs with cliff racers as far as I can tell. Typing pcb has no effect on performance.
Regarding any additional mods, I have No additional mods running aside from DesuChan's race mod to add the cute elf race. Aside from that, it is a fresh install of Morroblivion. These issues also were occurring Before I installed the race mod.

#1
I've noticed Cliff Racers have animation problems. No offense inteded, when it unites with a posible low-graphic cards it may cause that.
It probably will be finished when Hashmi1 finishes his 'Creatures Reviewed' series. Or at least when he finishes Cliff Racers.