Second issue was due to disabling either of the graphics cards.
[speculation]this caused maple to run entirely on the processor, which is what used 70~90% of the CPU[/speculation]
enabling both graphics cards and cleanbooting
(search: msconfig -> services tab; check "Hide all Microsoft services"; disable all; apply; restart)
fixed the issue. I can run maple on windows 8.1 taking 5~10% cpu with both of my graphics cards enabled.