Can someone help me troubleshoot my issue? I have installed a radeon Vega 56 GPU in my Mac Pro 2009 5,1 but I get no video. Have aux power to both 8 and 6 pin power slots. Running 10.13.6.

Computer boots, but black screen. Thoughts?

So here was my solution: My issue seemed to be a power issue. I performed/did/installed the Pixlas mod, grabbing power straight from the PSU and not from the motherboard. Computer booted right up and as expected the video came on after the drivers were loaded. No boot screen available, which is fine with me.


macvidcards.com suggests installing your video drivers before doing the hardware swap.

  • The drivers are native with the OS. – Mark Jul 24 '19 at 14:17

That card is not compatible with your computer. This thread suggests it is because your PSU is not powerful enough. You would have to replace your PSU with a higher wattage unit. You would also need the drivers loaded prior to install, like Brian said.


  • That's unfortunate – HackSlash Feb 18 '19 at 16:06
  • Not really. Computers last longer than most people need them. I've never had problems with PCs physically breaking. I often put new GPUs in really old systems to keep them going. It's a shame you can't do that with these. The OP should be able to pop in a new PSU, and GPU with no problems. It's a testament to their quality that he can't. – HackSlash Feb 18 '19 at 16:28

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