Mac Pro 3.1 AMD Radeon HD 7950 El Capitan Install

Is that a Mac or a PC card?

Have you tried with only one monitor connected?

What shows when you boot?

Was the El Capitan install successfully conpleted?

I suspect there was a problem with the install, not the monitor/graphics card.

I have a Mac Pro 5,1 with an AMD Sapphire Radeon HD 7950 card i.e. the one that shipped as standard with Mac firmware. The drivers for this card are built-in to OS X. I only have one monitor connected but it works fine in Yosemite, El Capitan, Windows 10, and anything else I throw at it.

If you have a PC version of this card - even a re-branded third party version then it is possible to 'flash' them with Mac firmware. Generally you need to do this in Windows, I used Boot Camp to flash another different card a HD 7970.

I have this card, in a mac pro from 2010 and it's fine, so--maybe try changing the switch on the card from one position to the other one. yes, there's a switch on there-one position is for PC and one for Mac. In the manual, sometimes, the direction on which way to go is reversed. other than that, maybe try zapping the pram?? I have to side with what IIIaass said....maybe it's the install???

JB

Anybody experiencing sleep issues with their AMD Radeon HD 7950 3GB and El Capitan? I found the following information on the web.

micdim wrote:

Anybody experiencing sleep issues with their AMD Radeon HD 7950 3GB and El Capitan? I found the following information on the web.

Note: That graphic comes from the tonymacx86 website not an official AMD website. The information on the tonymacx86 website is aimed at people building what are colloquially referred to as 'hackintoshes' which are not real Macs. Therefore the information in many but not all cases does not apply to real Macs.

For real Macs running OS X only Apple provide official drivers for AMD video cards. Sadly Apple have a long reputation of producing only mediocre drivers at least in terms of performance and features, generally they work well enough. While Apple still do provide drivers in El Capitan for cards like the Radeon HD 7950 and HD 7970 Apple never officially sold these cards. I have not personally had any problems with my Radeon HD 7950 which is a proper Mac edition with original Mac firmware as supplied by Sapphire. However most of the time I am still running Yosemite.

The Apple drivers for AMD cards are built-in to OS X so the only way to get newer ones with any hoped for fixes is to upgrade your version of OS X.

Thanks John!

I just upgraded to El Capitan. No problems so far!

Thanks again for your help.

Micdim

I'm using the HD7950 Mac (genuine version) in a MacPro 4.1 with a LaCie 526 monitor. The combination worked perfectly with OS 10.8 and 10.6. But 10.11 limits my maximum resolution to 1900x1280, when there used to be at least two higher options in the Displays preference pane. Radeon tech support says the drivers are built into the OS and not available separately. La Cie (now Seagate) can't help either.

Any suggestions?

maybe I can help you, earlyzee. Assuming the switch on the side of the card is in the correct position, the only other thing I can suggest is going to system preferences, then Displays, then option click on scaled which should give you a few choices extra, other than that....SwitchResX?

good luck

John B

In Display Preferences what is available when you depress and hold the Option key and click on Scaled?

Try using an app like

Switch X

http://www.madrau.com/

or Display Menu for the Mac App Store

Thanks, Johnb-one and Illaass, but I already tried the option key and it reveals only lower-resolution choices (down to 600x800). I upgraded to El Capitan by installing an additional drive for it, so I can now boot to either my 10.8 drive or my new 10.11 drive. Here's what the Displays preference panes show in both OS's...

OS10.8.5:

OS 10.11.6:

Mysterious, right?

You can try messing with the EDID

http://www.insanelymac.com/forum/topic/281412-how-to-advanced-edid-injection/

http://whitehatty.com/2012/04/28/mac-os-x-display-edid/