Sapphire Radeon R9 280 OC 3GB DDR5

Have you seen this previous discussion:

Radeon R9 280x on Mac pro

I have seen information that suggests a Radeon HD 7950 = an R9 280 and a Radeon HD 7970 = an R9 280x. Your results seem to confirm that. I have no idea why two different model numbers would be used for apparently the same card(s).

Do you have a link to a picture of the card? I ask because some versions of the card would match the original 'reference' design and that would be the design for which Apple's drivers are written and for which the pre-built Mac 7950 firmware is intended. There are two approaches to flashing a PC version of this card, one is to use a firmware image someone else built for a standard i.e. reference HD 7950 (or presumably R9 280) or to use the additional tools to build one specifically for your card by 'appending' the Mac EFI code to the standard non-EFI PC firmware.

Note: If you don't have a 'reference' design card this may mean at a minimum one or more connectors do not work on the card however reports seem to indicate that otherwise the card will work. For example reference designs only have a single DVI connection and many non-reference designs have two.

maiams13 wrote:

Hello,

This is my card: http://www.sapphiretech.com/productdetial.asp?pid=C4D1B443-6105-4A63-85DE-1732CC 9C443D&lang=eng

I must say that it works fine using Bootcamp.

Thanks for the link. As you obviously know and I can now see it has two DVI ports so does not count as a 'reference' design. As a comparison the following is a standard i.e. reference HD 7950 - http://www.sapphiretech.com/productdetial.asp?pid=D9A64D5D-60F4-41C4-BF78-8773BA 2C3974&lang=eng

The following is also a HD 7950 but looks more like yours but does have the same 'reference' mix of connectors i.e. only one DVI. http://www.sapphiretech.com/productdetial.asp?pid=083028EE-FE92-40C7-91D0-C88569 F5B115&lang=eng

Did you build your own firmware or just use someone else's?

Normally according to reports I have seen the only consequence of a non-reference design is that the second DVI ports just does not work but everything else does. I have not seen reports of VRAM errors like yours but did you also do the hardware mod to 'fix' the PCIe speed in a Mac? See http://forums.macrumors.com/threads/how-to-make-link-speed-2-5gt-s-to-5-0gt-s-on -ati-card-and-nvidia-card.1547340/

You can look under PCI in System Profiler to see if the Mac is recognising your card as 5GT/s or 2.5GT/s