Okay, this has been driving me insane, I don't know if it's been pestering any of you as much as it has been me but I've been relentless in my pursuit in figuring this out. See, we all know the incompatability between AA and the heatblur and how it kills frame rates, but I've had strange inconsistancies with this problem. First off 2x AA seems to work fine with Heat-blur. Othertimes I can even manage to get 4x AA to work with it without problems.
Anyhow, to get to the point I was having one of those times where 4x AA was working perfectly with heat-blur... until I went into the graphics menu to change an option, when I started the game again same old problem, game runs slow when the heat-blur kicks in. This perplexed me, so I decided to try something, I went out of the game, set my AA to 2x, tried running with heat-blur and everything ran fine as it usually does when AA is at this level. I played the game for a bit, exited and set my AA back to 4x. When I got back into the game (without changing any graphics options mind you), heat-blur worked once again without a hitch with AA at 4x.
So long story short, turn off your AA or set it to 2x, run the game with heat-blur, leave game, set AA back to 4x or 6x or whatever it is you enjoy running and play the game. It should work as long as you don't change any graphics options, if you do you'll have to repeat the process. This seems to be a workaround for the problem, atleast for me. I hope this information can come in handy for the rest of you as well.
For reference sake I'm running an ATi Radeon 9700 pro with Catalyst 3.9.
<center>-Death From Above</center>
Message Edited on 11/17/0308:40PM by ShadowHawk__