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Author Topic: NEW amd drivers in 10.13  (Read 2807 times)
Spacedust
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« Reply #15 on: June 30, 2017, 03:34:47 PM »

Interesting, 10.13 beta 2 update 1 is now showing PCI Information when using non flashed gfx cards


At least it's not displaying the name correctly Wink
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brockbackups
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« Reply #16 on: June 30, 2017, 06:06:08 PM »

Anyone know of the resistor that needs to be taken off of a RX 480 to get 5.0GT Link Speed?
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tomtomgps
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« Reply #17 on: July 02, 2017, 10:23:44 PM »

The reason we know which resistor  to remove on the 7950,  7970 or 280X is because they are basically  the same cards and there is a 7950 Mac edition. By comparing the 7950 Mac edition  to the 7950 Pc edition someone found out which resistor to remove, simply because it was missing on the 7950 Mac Edition card.  TBH, the 7950 was designed that way but from what I understand nothing guarantees that the RX 480 has a resistor  that can be removed without damaging the card and that would provide 5.0GT/sec on a MAC, in fact it's actually very unlikely. Since  AMD APPLE authentic cards were more expensive than their PC counterparts,  AMD probably used that  resistor   as a cheap way to differentiate  a PC Card from an APPLE card. From what I understand they used the resistor trick twice, once for the HD4850 and once for the HD7950. I do not know if AMD used that resistor trick for the HD5870 too, but from what I have read simply flashing a 5870 does not allow 5GT/sec on a Mac Pro.

For some reason NVIDIA cards on boot camp need to have a Mac EFI [EDIT: no need for a Mac EFI but it needs a firmware mod] in order to provide 5.0GT/sec , but they do not require any hardware modification.  In reality there very likely is a way to remove the 2.5GT/sec limitation on the RX 480 by altering its bios/ Mac Pro firmware or Mac OS X driver.

Has anyone tried to boot the Mac Pro with linux and the open source  MESA drivers to see what type of connection speed between the GPU and the Mac Pro is possible ? If the connection is 5GT under linux then we would know that the limitation is purely a software one.
« Last Edit: July 13, 2017, 05:11:36 PM by tomtomgps » Logged
Fl0r!an
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« Reply #18 on: July 03, 2017, 01:52:52 PM »

From my understanding it's a hard strap (AMD) or soft strap (Nvidia) to configure the PCI slots properly at boot time. It's possible to do the same from an EFI shell: http://forum.netkas.org/index.php?topic=13541.0

Rominator has found the necessary modification on lots of cards which never had an official "Mac Edition".
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