Hi - I'm just going to pass along some recent experience I've had with ugrading my video card to the x1900xt and then replacing the cooling system with an X2 fan on my macpro dual 2.66 'moral of my post, don't forget to put the thermal pads on all 8 of your video card's memory chips when adding the X2 cooler.' if you're interested in reading how I came to this conclusion read below: So I ordered the upgrade card and replaced my stock video card with no problems, all was well. I work on video and motion graphics and I definitely noticed an improvement in some of my motion applications. For fun I've been known to play World of Warcraft now and then.. which is where the biggest graphic improvment seemed to be. This is also where I noticed the fan noise of the x1900... not really a big deal to me, but I've been reading about the X2 cooler and that I could get rid of that occasionally loud noise. I ordered the cooler and it sat on my counter for about 2 months til finally thought, lets go ahead and give this thing a shot. Now I have to say this was a little scary, messing with my $400 video card putting this new cooler on... I followed the directions and all seemed to go ok. My only mistake was I didn't hook up the power to the video card the first time and was scared for a second when I went to turn on my mac and had no video. So then it was back to life as normal, working and occasionally playing wow. Everything seemed to be normal, but I was noticing when playing wow, I was getting graphical glitches, not when I first opened the game, but maybe after playing 10 minutes or so. This glitching only happened when I was playing the game.. never in any of my other apps. So I didn't even think anything of the X2 cooler, it just didn't occur to me. But the longer I would play, the more it would glitch. I knew it hadn't gltched like that before and I started to get freaked out that maybe, I had broke something when I installed this fan.. to me it didn't make sense that the fan itself would cause glitching. But if that were the case, why is it only when I play this game. Maybe it was the game? No, this was something different, it started when I installed that fan. So I lived with the problem for a few weeks because it wasn't a big deal, it only happened on that game. I did some research online, and saw that glitching can be the cause of overheating... I started researching peoples experience with the X2 and found that there was one step that wasn't clearly explained in the instructions. Included with the x2 fan are 8 thermo pads that have to be placed on each of the memory chips.. the original ati fan did not have anything any sort of covering on those chips, so I had no idea that was necessary. I pulled my card back out, and placed those pads on and the glitching has stopped. I just hope no real damage was done from not having those on there in the first place. I wanted to tell you guys about this just in case there were others of you out there that put this fan on your cards and missed this step as I had. Had it not been for playing wow, maybe I never would have even noticed a difference. Also, I'm driving two displays, a 30" and 15".