Do you mind taking a look at my post on the previous page about my temps? The office it is in tends to run hot in the evening and the temps on the 6450 seem to be really hot for me. I tried both types of Sunon fans that have been mentioned here and both perform about the same (considering they both have about the same spec cfm). The switch always keeps the fan in high mode and it is much louder than any other system in the room. In high mode the Sunons are definitely putting out a decent amount of air and holding your hand up to it the air is pretty dang hot.Don't expect it to be at 30°C/90F, those are older process silicon, they are designed to run at 50-60°C/120-140F basically all the time, and hardly ever be shut down.
I'd be willing to try any fans you or anyone else may recommend, I just need to find a good balance of temps to noise.