I've done some profiling of my code and nothing sticks out as a problem. Algorithmically I have kept things very simple but I do have a fairly deep object tree. Add onto that the fact that I have a crazy number of threads running and I've started to believe the OOP and multi-thread naysayers. Since I'm less than a month from having a demo ready to show off I decided it was time to get some real world data. I know it seems a little late but nothing worse than some AAA PC titles I've worked on. :)
I managed to dig up a friends old laptop. Not totally bottom of the line but a 500 mhz processor and an integrated video card with a whopping 16 megs of VRAM. Running at 800x600 in a window is a definite no go. Everything runs but way too slow. The good news is switching to full screen brings everything in line. Smooth as silk and totally playable.
So the next step is doing a little research and tweaking to my game to take the hardward into account. The good news is that I have fullsrceen as a fall back option. I'm also going to look at turning off alpha on slower systems and potentially using smaller textures. But all in all I feel a lot better knowing where I am.