I haven't looked at this at all but that doesn't sound high to me. The bitmap drawing code is very unoptimized and has to touch a large number of pixels. CPUs aren't GPUs, so you can expect that soon we will actually be using 100% of the CPU all the time, and it will almost all be in rendering, because even though we will obviously be making much more optimal bitmap drawing routines, we will be drawing a lot more stuff!
- Casey