We had a hard drive crash with 10.10.5. I replaced the hard drive, reloaded 10.10 using my native ATI 2400 XT, ran all updates, installed latest web drivers, added the nvda_drv=1 boot argument, shut down, popped in the GTX 970, heard the chime for start-up but did not get to desktop. I am aware that the boot screen won't appear. I put the GTX 970 in a PC and got video. What could be the issue?

  • Have you tried using screen sharing from another Mac to diagnose the problem? I find myself doing that often with the PC graphics card in my Mac Pro. – NoahL Jan 26 '17 at 4:42
  • Update: adding a 8800 GTX, which should be slightly higher in TDP, produces one loud long single beep, sort of like a screech. Immediately pulled the power, thinking I had done some irreparable damage to the computer, but research suggests that this is a beep caused by an underpowered video card. Is it safe to say that it's a power issue? – Don Mick Jan 26 '17 at 6:08
  • Pull the GT8800. Then make sure BOTH 6-pin power connectors are attached to both the computer and the GTX970. You ALWAYS need to use all of the power ports on graphics cards – NoahL Jan 26 '17 at 6:56
  • Sorry, that should have read his replaced instead of Addong. I took out the 970 and put in the 8800, which is what we used before the 970 arrived. The 970 results in black screen with a boot up chime and the 8800 by itself results in the beep that suggest no power. Thoughts? – Don Mick Jan 26 '17 at 10:09

This was solved by:

  1. making sure the PCIe cables were properly seated, on the Mac Pro motherboard.
  2. clearing NVRAM by cmd + option + p + r.
  3. installing Nvidia drivers (which adds the nvda_drv=1 flag as part of the installer).
  4. place GTX 970 in slot 2, making sure PCIe connection is on tight.
  5. system boots properly.
  6. shutdown, then move card to slot 1, making sure PCIe power connection is on tight.
  7. system boots properly.
  • Welcome to Ask Different! You can mark your own answer as accepted using the check mark on the left. – grg Aug 16 '17 at 10:48

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