I have a strange (and annoying) issue that just won't seem to go away and I'm curious if anyone else has experienced the same before I start the process of pulling out cards and trying a zillion variations on this. Short version specs: - Mac Pro 2009 w/firmware update to 5.1 - OSX 10.10.1 - Same behavior on builtin 10.10.1 nvidia drive and current web driver - (2) cards, but currently only one being used - EFI (via MacVidCards) GT640 and PC non-EFI GTX Titan - (4) monitors - all connected to the Titan. What happens is that at least 50% of the time the PC boots up (either cold *or* just from a restart) only 2 monitors are detected and the other two don't get detected at *all*. At the moment the ones that come up when only two work are the first DVI port and the HDMI port on the GTX Titan, while the second DVI and the DisplayPort connectors will stay dead. Couple of additional bits of weirdness that is repeatable: - Doesn't seem to matter whether I use the builtin driver or the web driver from Nvidia - I did for a while have one of the monitors connected to the GT640 for a boot screen, and when I do that it still 50% of the time only comes up with two monitors but in that case 1 will be on the GT640 and the second will be the first DVI port on the GTX Titan - Getting it to come back *correct* seems to be reboot, PRAM reset, and cross fingers. Sometimes it comes right back up with all four working and sometimes it comes right back up with the same old two. I just keep doing it and doing it until I get a boot with all four. - When it boots with all four, I can use it all I want - for days and days and days with no trouble at all - until I either reboot or shut it down and bring it back up. - I have a bootcamp partition and I can boot to that and all four monitors come up and work each and *every* time I have been reading a great many things about lost display preferences and external monitors not being detected in 10.8/10.9/10.10 and there are a ton of crazy things out there - not sure whats real and whats not. For example I've seen: - Its having 2 cards in your Mac Pro - Its using a non-EFI card - Its using a SSD boot disk (and some crazy timing-related issues to the window server) Has anyone else had similar behavior with theirs using more than 2 external monitors? I'm just trying to gather as much intel as I can to try and figure out what the real pattern is here.