|You can probably mix them, but understand that any combination will only run at the speed of the weakest (slowest) stick. Here's what you have:|
Kingston = DDR3-1333 @ 667MHz
Crucial = DDR3-1866 @ 933MHz
Corsair = DDR3-1600 @ 800MHz
The Kingston is already bottle-necking your system because it's only running at 667MHz. And if it's by itself in single channel mode, it's causing a further bottleneck. At the very least, you should be running a matched pair of DDR3-1600. A matched pair of DDR3-1866 would be even better. Timings aren't all that important because they can be manually configured in the BIOS. And to a certain extent, so can the frequencies.
Didn't you ask about this before?