Ok I found a solution that works for me that'll do until they bring out a hotfix. I simply upped my page file size, it's now sitting at 2500mb inital, 4000mb max. All my graphics settings in wow are cranked down to minimum, and since then I haven't had any problem, was able to quest, instance and play numerous AV games. It's a bit annoying having to have the graphics down low but at least I can play. Haven't starting experimenting yet by slowly upping the graphics settings, I'll keep ya's posted.

This temp solution prolly won't work for everyone, but hope ya's benefit from it. For those who don't know how to change your page file here's how ya do it.

Right-click 'My Computer' > Properties > Advanced Tab > Perfomance Settings > Advance Tab > And click the Change button under Virtual Memory. Then click on Custom Size and put in your values.

The above figures work for me, normally you don't need such a large page file, but I haven't noticed any adverse effects on my system -shrug-

Darth, any word yet on the macro situation?

I can reproduce this 100% on my system and I'm not the only one having issues.

Basically the problem is any sort of macro with a conditional, e.g. [target=player] lowers frame rate by a decent amount. Have enough macros and your game ends up unplayable.

I've tested this a number of times but here's my latest test:
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Methodology:
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1) I deleted my cache and interface folders. I deleted my account folder under WTF (kept the config.wtf file).

2) Loaded WoW and logged in.

3) I went to a nice out of the way spot in Hellfire Peninsula that can be only reached by flying and has no mobs or other traffic.

4) I stared at a wall.

5) Made a note of my FPS over a nice period of time based upon both WoW's frame rate display and FRAP's (they matched).

6) I did a /macro and started to add macros with fixed icons (no ? icons) with the text: /cast [target=player] Renew

7) Kept adding these one at a time keeping watch of my average FPS.

After about 10 of them I closed the macro window and waited for the FPS to settle and made a note of it.

9) I went through and removed all the [target=player]'s from the macros paying attention to the average FPS.


Results:
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1) The initial average FPS at step 5 was between 102 and 112 FPS.

2) Steps 6-8, each new macro lowered my FPS until after about 10 of them my FPS was down to around 70fps staring at this same wall (didn't move camera).

3) After removing all the conditionals in step 9 my FPS returned to between 102 and 112 FPS.

Conclusion:
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Conditionals in macros put a MASSIVE burden on the CPU even if they're not actually being used for anything. Purely by existing they chew up a large portion of the CPU and it's a large detrimental effect to performance. Simple conditionals like this shouldn't cause this sort of problem.

Could it just be some buggy code that's causing it to consume more CPU than it should?
Or could it be some sort of client->server interaction for some reason? My latency today is 230ms (where I currently am) which is about the lowest I've seen it, but usually it's around the 450 to 550ms mark.

Althor, something else that is relevant to you and others seeing performance problems with conditional macros: there is a simple change you can make to your macros to make them perform at the same speed they did before 2.1.0. The issue has to do with real time status updates for your macro buttons. In 2.1.0 we added a feature to show the proper dynamic status of your macro buttons on your tool bars. If the macro has conditionals, this complicates the parsing to determine what spell or action's status should be associated with that button. Since this status can change at any time, it is evaluated every frame. We are working on making this process faster, but in the meantime, there is a simple change you can make to each of your scripts that will make them parse faster. Say your macro conditionally casts distract. You can simplify the parser's job by giving it a "hint" as to what spell it should display status for that macro. In this case, you would put the following line at the top of your macro:
#show Distract
This tells the parse to skip any parsing of conditionals, and just show dynamic updates for Distract on that macro button all the time. Performance-wise, this should be equal to not having the conditional in the macro, but you get to keep the conditionals.
If you simply want no status at all:
#show none

who are you again?

Just a note: I'm using nVidia and I have no performance issues, I barely crash at all actually.

That what, for the first time ever?