Modo's still in its early stages, give it some time. Although they've begun on the road towards animation and being a full-featured rendering package, it's core use is still modeling.

Its OpenGL is actually behind Poser's in terms of speed. I have a G-Force 8600 GTS video card, and a 64 bit system with Vista 64 bit, 6 gigs of RAM, and an AMD dual core CPU, and modo seems to strain even with that.
Hopefully they'll work that out. They'll have to.