Beware - long post awaits (but thanks in advance to those that have the time to get through it). I have a December 2006 Mac Pro with the following stats: Model Name: Mac Pro Model Identifier: MacPro1,1 Processor Name: Dual-Core Intel Xeon Processor Speed: 2.66 GHz Number Of Processors: 2 Total Number Of Cores: 4 L2 Cache (per processor): 4 MB Memory: 6 GB Bus Speed: 1.33 GHz Boot ROM Version: MP11.005C.B08 SMC Version (system): 1.7f10 Serial Number (system): CK6470PDUPZ Hardware UUID: 00000000-0000-1000-8000-0017F204E3BE Along with the stats I think it's worth mentioning that I have 2GB of Apple Ram (that came with the mac) and a further 8GB worth of crucial RAM all paired up correctly over the 2 cards. I think it's also worth noting that the different makes of RAM was placed in the mac long before these problems started. Over the last year or so I've noticed it beginning to freeze more and more in a variety of different ways: One way which I only ever saw occasionally (although as of Sunday I saw it twice in one day), is the grey screen falling from the top telling me that I'll need to restart. Update: In between writing this out and posting this this has happened more and more frequently); Another is the screen (apple cinema display 23") just turns black (as if it's turned off) and I can't turn it back on again. If something is playing that continues to play (music, video in QuickTime, video in FCP, basically anything that s running continues to run). However, the keyboard shortcuts for quitting, restarting, shutting down no longer work; The third is similar to the last in that the keyboard no longer works, however the screen remains on and whatever is playing continues to play although in this case the audio does continue to work but the video doesn't. I can move the mouse across the screen but cannot click on anything. This happens in a variety of situations and there doesn't seem to be a constant way of invoking it other than opening another application too quickly (although this doesn't happen all the time I do this a and can occur when I'm doing other things). For example, just working in final cut can cause some of these things to happen, but it can ask happen in less power sensitive tasks such as working in Pages. The only time the black screen crash happened with any certainty was when I tried running the sims 3 on release (but without going through receipts I'm not sure when I bought the sims compared to when I installed the RAM. And even then I did nothing specific in the game it occurred seemingly randomly. In addition, I keep getting graphical errors on the screen - garbled lines of colour appearing, and windows taking sharp diagonal dives (for example, the left half of a window will be fine, the rest will be all flattened at the bottom of the screen). I know this is a lot of information in one post but I'd rather people that can help have as much as they can from the off. Additional notes: hard drives have been changed from the original that came with it and now sports four hard drives. All of these have been tested as much as I can and seem to be working fine. I have a fire 800 time machine attached. The front ports on the mac don't appear to be working too well, with some devices the 400 port won't work while that same device will work if I plug it in to the back (via the monitor). Other devices will work with this port. I've had it a couple of times now where if I have a few USB ports in use and I eject and pull my iPhone from the dock (which is plugged directly in to the back) it ejects all the other devices. Not sure if that has anything to do with the freezing issue, but I figured I'd mention as much as I could here. I think that's about it as far as odd behavior goes. Looking over what I've written my gut says "graphic card issue", but I would have thought this would cause one particular problem rather than a range of them (and if its been happening for some time I would expect it to have a big "final" crash by now). I'm hoping it's not the logic board, but I wouldn't know what issues with that look like. Any ideas? Any more information needed? Any tests I can do to try and narrow down the problem? Thanks in advance for reading (if you got this far) and any help you can offer.