I have worked around the problem where GCC 4.0 would miscompile certain runtime primitives on x86 with the -fschedule-insns optimization. Factor 0.79 still has the problem, however Factor 0.80 can be compiled with full optimization.
I'm hoping I can finish off Factor 0.80 today. The only thing I need to do is get the UI running on AMD64. Enough of the FFI works to support native I/O, however the UI still has problems. Perhaps it is an FFI bug, or my SDL, OpenGL or FreeType bindings are not 64-bit clean. It should not be hard problem to solve.