Hello fellow forum members. Looooooooong time lurker here (seriously, y'all have solved MANY a problem of mine - THANK YOU) but I finally had to create an account because I'm beyond flummoxed. I have a 2006 Mac Pro with upgraded CPUs, 16GB, 5770, SL. Most recently, an issue has been happening that I can't figure out. I will be doing some mundane task like watching 'Flix / iTunes movie, listening to music, or just browsing the interweb when the display cuts out, the audio is killed (if there was audio), and the front fan does this weird on / off cycle (1.5 seconds on, 2 seconds off, repeat). The computer is completely unresponsive - no video, audio, mouse and keyboard are useless. At this point, I have to force shutdown the tower and restart. However, I have also gone to bed only to wake up to that dreaded cyclic fan noise so it's not symptomatic with active use. I've run a mem text using the OEM install disk but it's showing up as ok. I've moved the memory around. I've removed and reinstalled the video card. I don't know what is going on. Here is a link to an audio recording. It's short and starts at :04. I will submit links to copies of the logs tomorrow. Now, let me just say that I am not planning on getting rid of this computer since I got it for dirt cheap and I have VERY specific iTunes needs - namely iTunes 11+ sucks balls because multiple playlist windows was disco'd (I teach fitness classes and need to have multiple playlists open to easily create them). That and I like Front Row too much. I have a 2014 MBP (from work) that serves as a tertiary back up system so I'm not really stressed about hardware. Plus, I'm not interested in upgrading for the sake of upgrading - if the current hardware does what I need it to do, I'll keep it until it completely dies. With that said, I'd LOVE to get your thoughts on this. At first I was thinking that this issue stemmed from the CPU swap and the F/W update but when I stopped to think about it, this same exact issue happened ages ago when it had the 1900XT installed, just not as frequently (this issue has happened 5 times in the past 2 days). Shout out if you have questions / suggestions. I could really use your brainpower as I've exhausted my own. Many thanks in advance!!!