hd7950 no low level boot screen

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Level 1

28 points

hd7950 no low level boot screen

I just bought a Sapphire Mac Edition HD7950 from OWC. If the switch is set to setting two the machine will boot straight through to the OS with only a split second of grey. If the switch is set to setting one the machine will boot straight through to the OS with only a split second of grey. Holding down the option button on either switch setting results in no video out at all: only a black screen forcing a hard reboot. I am running OS x 10.11.6. Any ideas?

MAC Pro 2010-OTHER, OS X El Capitan (10.11.4), 12 core 3.43, 128 GB

Posted on Jul 25, 2016 8:44 PM

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Answer 1

lllaass

Level 10

210,519 points

Jul 26, 2016 1:03 AM in response to Pheidius1

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

https://support.apple.com/en-us/HT201295

About NVRAM and PRAM

https://support.apple.com/en-us/HT204063

- Try bootting to Recovery and repair the startup disk

OS X: About OS X Recovery - Apple Support

https://support.apple.com/en-us/HT201314

Next, contact OWC

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Answer 2

Pheidius1 Author

Level 1

28 points

Jul 26, 2016 3:46 PM in response to lllaass

I already did SMC reset and Pram as well to no avail. I can't get to any of my other boot partitions much less recovery as the option key results in no video at all. I have contacted OWC.

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