SET timingMethod ?

They're different timing modes for the game that will do different things depending on how your mutlicore processor behaves. This command was first introduced in 2.0.3. timingmethod 1 is generally for systems where the cores do not synchronize. You might run into issues like your framerate caps at 64 instead of your vsync value. timingmethod 2 is a higher resolution timing method and you won't hit the cap with that.

Q u o t e:
Oh, well I have a single core processor, so this wouldn't help the fact that my game locked up so hard that I can't even boot into Windows like I mentioned in my thread that nobody replied to here:

http://forums.worldofwarcraft.com/thread.html?topicId=3168245069&sid=1

An application can't crash a system to the point of it not booting up. If you have distorted graphics on the BIOS and on load screens, your video card gave up on you. Sometimes it might be recoverable such as a dust buildup so you might want to check it.

Q u o t e:
it seems to be the other way around for me
2 frame rates drop like a rock and 1 every thing is fine
this seems backwards to me

From what I understand, 2 can do that if your computer spends too much time thinking. It basically tells the game that it can think more often than being constrained by a time limit. You might experience similar behaviors with timingmethod 1 with a media program up, such as Windows Media Player. Those programs change the timing systemwide while they're running.

I'm not sure. I was told that the AMD Dual Core hotfix does not affect the game since it does not use the command that it was meant for. You can try it as it may affect other programs or drivers on the system.