Radeon HD 5770 or 5870 in Mac Pro 1,1

They are both compatible. However, that MP model only has PCIe 1.0 slots so the 5870 won't provide much if any improvement over the 5770. The 5770 performs just about the same as a 4870 in that model. It's all slot limited.

You are limited by the bandwidth of your PCIe 1 Bus. The extra performance of the 5870 over the 5770 would be wasted.

Be sure the card you buy has Apple firmware. PC-only cards will not show a picture under Mac OS X, and flashed PC cards will not show a picture until Mac OS X isfully operational, so they are useless for debugging.

No crossfire under Mac OS X. Don't bother with multiple cards unless you are running more than the three displays supported by the 5770.

Drivers are in 10.6.4 and later.

You can only use one GPU at a time, so having one or four is meaningless. Only one GPU at a time can be in a 16 lane slot and that means Slot 1 or Slot 4. In other words there is no benefit from two in any Mac Pro except to run four monitors at a time.

Yes.

I thought NVidia and AMD had drivers enabling use of some PC cards with Mac OS X 10.7. Except that they do not have an EFI rom so they only display something once the drivers are loaded by Mac OS X. Is this true ?

Today, A PC card flashed with Mac Firmware will only produce a picture after Mac OS X is fully loaded and operational. That is fine, provided when you want to change boot drives, or do maintenance, or re-Install something, or Debug a problem, you can live with nothing on your display. Most Users can not.

Cards released by Apple and fully supported by current versions of Mac OS X were built with EFI firmware ROMs.

"Hacker" sites try all sorts of currently unsupported-by-Apple stuff. Some of it works great. But those sites are not going to provide support for you when things go bad. If you need your Mac to be reliable for doing productive things, stick with what Apple supports TODAY, unless you can provide your own support.

In a few months, the situation may be different. Or maybe not.

I agree with you. But it seems some NVidia graphics cards currently work with nothing else than the new drivers, no need to hack the card. Which could be acceptable to some people. I'd still suggest keeping the original card, in case a boot-up diagnostic is required.

Indeed, it is not supported by Apple. I fully agree with you that this might not be a good idea for someone depending on their Mac Pro for work.

Btw, i see you post tons of great advice on these boards, thank you!

Thanks for your kind words.

Grant,

FWIW, flashed PC cards do not display at startup if connected using a DVI cable, but will if you use VGA. If you happen to have a monitor that can hot-switch between DVI and VGA you can actually boot with the monitor set for VGA then switch to DVI after startup by simply running both DVI and VGA cables from the card to the monitor's ports.

As it happens to be I have one of the flashed 5770 cards in my Mac Pro. Just thought you might find this interesting.

Thanks, Kappy. That may come in handy.

Your kind and supportive words are appreciated as well!

You well deserve all the kind and supportive words you get, Grant. You do great work here and are a wonderful source of information.

Best regards.