Radeon RX 560 in flashed late 2009 Mac Pro running Monterey goes past apple screen then nothing

[Happy4]

I tried a good working Asus Radeon RX 560 in my flashed Mac Pro and it will show the apple and the bar going across, but then nothing. I know it won't show a splash screen, but I left it for quite a while and it just had a blank screen.
This Asus card does not have an auxiliary PCI plug-in. Could that be the issue?

 

[Macsolver]

The genuine Asus Radeon RX 560 has an 8pin PCIe power connector. This must be connected to the two 6 pin mini power sockets on the Mac pro login board with a Y cable, not just one socket to an 8 pin PCIe plug.

If the GPU does not have an 8pin PCIe power socket, it is likely a fake older GPU with a flashed ROM which is why the Mac is not booting. Check on line for the manufactures info and details of the well documented fake GPUs.

I seem to remember that OSX High Sierra final version included support for the RX5XX GPUs, and later versions of OSX too.

 

[Happy4]

This is where my problem lies. The card was purchased for an Alienware X51 and had to be a "E" style low power consumption design. I have cables, but the card has no power plug-ins.

 

[Macsolver]

You may be able to get it working with Monterey if you create a new USB OpenCore Legacy Patcher installer booting from an older version of OSX with the GPU in place at the time you create the new USB installer. If you can boot from the new USB Monterey installer, you should be able to save a new set of EFI patches to the existing Monterey Boot disk that should then work with the card.

Might be a idea to first check that the GPU power draw on the PCIe buss is less than the combined limit for the Mac Pro PCIe power buss (allowing for all PCIe cards). I have seen it somewhere on line but I can not remember what it was, sorry.

 

[Macsolver]

The Apple Manual for the 2009 Mac Pro states "Important: Combined maximum power consumption for all four PCIe slots must not exceed 300 W." (Page 21)

 

[pm-r]

I tried a good working Asus Radeon RX 560 in my flashed Mac Pro and it will show the apple and the bar going across, but then nothing. I know it won't show a splash screen, but I left it for quite a while and it just had a blank screen.
This Asus card does not have an auxiliary PCI plug-in. Could that be the issue?

I don't know but I would suggest searching in the xlr8yourmac.com site if they might have a record of such Mac Equipment, but they used to keep quite current many years ago but I'm not sure if that has changed lately or not.

Anyway give it a shot searching here: xlr8yourmac.com

I would suspect that support for Old Mac legacy computers is getting pretty thin and very little support these days.



- Patrick
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[Macsolver]

Hi,

Had a play around with a Mac Pro 5.1, Monterey and various GPUs. What you describe is the expected behavior when swopping GPUs without updating the OpenCoreLegacy patches with the new GPU in place. Boot using a High Sierra disk (supports NVMEs) with the OPCL application and the new GPU installed. Update both the EFI and boot patches on the Monterey boot disk. Reboot when suggested by the OCLP application. If it boots into HS, next boot select the Monterey EFI partition if possible or start with just the Monterey boot disk installed for the first time. When booted into Monterey, you can re run the OCLP patches again and it will clear the caches so it boots into the Monterey boot disk thereafter.