SOLVED - I was just looking in the wrong place
So yeah, I have a bit of a problem...
NVidia Control Panel is responsible for choosing which programs on my computer need dedicated graphics (650M) and which only need the integrated card, but it can only do so for executables, so I can only get Tekkit to run on the integrated one, which is a pain. Even on lowest settings, I can't double-tap space quickly enough to go into fly mode.
Any thoughts on getting/making a .exe launcher?