[REPOST FROM AI--post your thoughts/corrections please]
I've decided to start a new thread because some exciting stuff is going on (some fresh news in here for people who don't know, read on!):
EFI, Apple firmware, and ROMs.. how does it all fit together?
From what I've found out, most modern video cards are EFI as well as BIOS compatible. (1)
'PC' video card ROMs are only 64K, whereas 'Mac' cards are 128k. The reason for this is so that Apple can have full-color and full-resolution boot sequences and boot menu (what you see when you hold down option).
Therefore, whatever ends up happening, all PC video cards on a mac (if they run at all) will have a black screen until the OS loads the driver. This hand-off between the video card's ROM driver and the OS driver occurs just before the login screen. (2)
Whenever you hear about people soldering in new ROM chips to a PC video card to make them work with a Mac, this is why.
YOUR MAC WILL NOT BOOT without a Mac Video card in the slot AND a monitor connected to it (4)
Why PC Video Cards don't work (or do they?)
Actually, PC video cards work FINE in a Mac Pro (2), it's OS X that doesn't work.
OS X needs a driver to run these cards, which demonstrated by the fact that at least two PC 7800 GTs have been reported to work out of box. (2)
Before you ask, they were PNY and eVGA brands (2) (The eVGA Part No was 256-P2-N515-AX) (4).
In both cases, the stock 7300 (Mac w/128k ROM) was left in slot 4 and a monitor plugged into that card.
How could this happen, you wonder, if the only OS X driver for the 7800 is for PPC and not x86? Simple: the G70 chipset used by the 7800 GT is also present on the ... you guessed it, QUADRO! (cue the oooooohhh's).
But the PC x1900's don't work with mac, and they have a driver!
Well, perhaps they do. There has been 1 report of an x1900 XTX [sic.] working out of the box in a mac pro, but that was unsubstantiated and the poster has since disappeared from existence. (3) Apparently, the card was detected as an XT, not an XTX.
It would not suprise me if at least one manufacturer had some sort of weird chipset which other people who've tried x1900's did not have, and that chipset may work with the Mac Pro.
It could also be that some people who have tried the x1900 did not wait to see if the 'black screen' would go away. Again, the temporary 'black screen' is normal, so we know that even a card that WORKS would have this issue.
Finally, people need to leave an Apple card plugged in and a monitor connected to it or their machine will not boot!(4)
Fun Facts
- The Mac Pro has a 1KW PSU.
From barefeats:
-Can you use Windows PC PCIe graphics cards in a Mac Pro? No. The Mac Pro requires special firmware.
-Can you use G5 PCIe graphics cards in a Mac Pro? No. They have different firmware.
-Can you take a Mac Pro PCIe graphics card and run it in a Windows PC? YES! You may say, "Why would you want to?" But this points to the fact that a company like XFX or ATI could, if they want to, release a "PC and Mac Pro" version of their graphics cards.
-SLI DOES WORK in the Mac Pro, though it should be noted that there can only be ONE 16x slot, so there may be no point. Here are the possible PCIe configurations (configurable by software):
So that's the news as I see it, here are the sources:
1: http://strangedogs.proboards40.com/index.cgi?board=experiments
2: https://forums.macrumors.com/threads/230505/
3: http://discussions.apple.com/message.jspa?messageID=2916283#2916283
4: http://forums.macnn.com/65/power-mac-and-mac-pro/308387/pc-pcie-video-card-working/
Clips from source 2:
REPORT 1:
REPORT 2:
I've decided to start a new thread because some exciting stuff is going on (some fresh news in here for people who don't know, read on!):
EFI, Apple firmware, and ROMs.. how does it all fit together?
From what I've found out, most modern video cards are EFI as well as BIOS compatible. (1)
'PC' video card ROMs are only 64K, whereas 'Mac' cards are 128k. The reason for this is so that Apple can have full-color and full-resolution boot sequences and boot menu (what you see when you hold down option).
Therefore, whatever ends up happening, all PC video cards on a mac (if they run at all) will have a black screen until the OS loads the driver. This hand-off between the video card's ROM driver and the OS driver occurs just before the login screen. (2)
Whenever you hear about people soldering in new ROM chips to a PC video card to make them work with a Mac, this is why.
YOUR MAC WILL NOT BOOT without a Mac Video card in the slot AND a monitor connected to it (4)
Why PC Video Cards don't work (or do they?)
Actually, PC video cards work FINE in a Mac Pro (2), it's OS X that doesn't work.
OS X needs a driver to run these cards, which demonstrated by the fact that at least two PC 7800 GTs have been reported to work out of box. (2)
Before you ask, they were PNY and eVGA brands (2) (The eVGA Part No was 256-P2-N515-AX) (4).
In both cases, the stock 7300 (Mac w/128k ROM) was left in slot 4 and a monitor plugged into that card.
How could this happen, you wonder, if the only OS X driver for the 7800 is for PPC and not x86? Simple: the G70 chipset used by the 7800 GT is also present on the ... you guessed it, QUADRO! (cue the oooooohhh's).
But the PC x1900's don't work with mac, and they have a driver!
Well, perhaps they do. There has been 1 report of an x1900 XTX [sic.] working out of the box in a mac pro, but that was unsubstantiated and the poster has since disappeared from existence. (3) Apparently, the card was detected as an XT, not an XTX.
It would not suprise me if at least one manufacturer had some sort of weird chipset which other people who've tried x1900's did not have, and that chipset may work with the Mac Pro.
It could also be that some people who have tried the x1900 did not wait to see if the 'black screen' would go away. Again, the temporary 'black screen' is normal, so we know that even a card that WORKS would have this issue.
Finally, people need to leave an Apple card plugged in and a monitor connected to it or their machine will not boot!(4)
Fun Facts
- The Mac Pro has a 1KW PSU.
From barefeats:
-Can you use Windows PC PCIe graphics cards in a Mac Pro? No. The Mac Pro requires special firmware.
-Can you use G5 PCIe graphics cards in a Mac Pro? No. They have different firmware.
-Can you take a Mac Pro PCIe graphics card and run it in a Windows PC? YES! You may say, "Why would you want to?" But this points to the fact that a company like XFX or ATI could, if they want to, release a "PC and Mac Pro" version of their graphics cards.
-SLI DOES WORK in the Mac Pro, though it should be noted that there can only be ONE 16x slot, so there may be no point. Here are the possible PCIe configurations (configurable by software):
Code:
. . . . . . . Slot 1 . . . Slot 2 . . Slot 3 . . Slot 4
Option 1 . . 8-lanes . . 8-lanes . . 1-lane . . 8-lanes
Option 2 . . 8-lanes . . 8-lanes . . 4-lanes . . 4-lanes
Option 3 . . 16-lanes . . 1-lane . . 1-lane . . 8-lanesSo that's the news as I see it, here are the sources:
1: http://strangedogs.proboards40.com/index.cgi?board=experiments
2: https://forums.macrumors.com/threads/230505/
3: http://discussions.apple.com/message.jspa?messageID=2916283#2916283
4: http://forums.macnn.com/65/power-mac-and-mac-pro/308387/pc-pcie-video-card-working/
Clips from source 2:
REPORT 1:
REPORT 2:
