I have this issue whenever I try to install two R9 280x's at the same time - I got three and they're all from different companies. Whichever constellation I install them in, once I insert the second card, it does the BSOD with the 3b error code (driver related) or a complete crash with no error message or system dump. Apart from this, the three different R9 280x's work, except the MSI card won't show properly in CCC, still shows fine in the device manager. The Gigabyte and the ASUS work fine when solo . . . So basically I need to figure out a way to run 2+ of these cards at the same time, without the terrible BSOD or any other kind of crashing... My system: CPU: i3-4130 - no OC. MB: Asrock Z87 Pro4 - flashed to newest bios 1.70. RAM: 2x16GB Sniper at 1600Mhz (auto setting, but also tried at 1333Mhz). OS: Windows 7 x64 Professional. Fresh and fully updated. APPZ: Avast Antivirus, CGMiner 3.7.2, various monitoring tools and other small professional programs - I don't run these when testing though! FURTHERMORE: One 500Gb Western blue and one ASUS DVD reader/burner. GPU's and DRIVERS: ATI 13.11 Beta 9.5 drivers and tried others. Onboard HD 4400 which I use for the desktop. MSI R9 280x Gaming - got the new vBios 015.039.XXXXXXXXXXXX ASUS DirectCU II TOP R9 280x - 015.039.XXXXXXXXXXX GIGABYTE R9 280x Windforce OC version - think it's 015.38.XXXXXXXXXX PSU: Toughpower XT Gold 1475w I get the crash before I get a chance to log into Windows or immediately after. I tested it with any two cards yes and with cards in both the x16 and the x4 slot. The computer starts up fine in safe mode, where I find the two cards in the device manager (tried Gigabyte and ASUS and MSI and ASUS) and I haven't been able to replicate the BSOD in safe mode. I tried the following: 1. re-installing cards in various constellations and slots, with driver-sweeper removing drivers completely and then re-installing. I've confirmed that both my full sized PCIe slots work with cards individually. 2. Flashing bios to newest version. 3. memtest86 and MemtestHCI, then I disabled the page file and ran both tests again - one full pass for each and running four isntances of MemtestHCI - I also tried with 2x2Gb GSkill, before upgrading to 16Gb RAM. 4. I tried 13.11 Beta 8, Beta 9.2 and Beta 9.5, with the same results and using driver sweeper in between to fully remove the earlier version. 5. Running in safe mode (with 2 cards), after using CCleaner to make sure almost nothing runs at startup... Worked fine. I was thinking about doing the following: 1. Upping vcore, even though I'm at the moment running everything at stock speeds (no overclock) and I fail to see why it would help. 2. Flashing the video cards bios, but not sure if I can find never versions or if I can use e.g. an ASUS vBios in a Gigabyte card and the other way around. 3. Trying out other older drivers - there aren't many left that I haven't tried though. 4. Even though this is a fresh install, I was thinking of making another fresh install of Windows 7 x64, with all updates etc and the necessary drivers to run everything, except the GPU (which I will wait with), then make an image of the file, so I can get back to a clean machine quickly, before I install GPU drivers. Finally install the GPU's - thus doing the drivers and basic installation before anything else - and I mean absolutely anything else . . . I sincerely hope someone can help me, as I am at a complete loss here . . . Hope anyone can help... EDIT: updated what has been tested and done.