Buy RX 560 GPU to install Mojave on Mac Pro (Mid 2010)?

@KidVid

Yes each PCIe slot has 75W allocated to it.

Each of the two PCIe power cables from the Mac Pro logic board provides 75W, this means the maximum available to a single card is 75W + 75W + 75W = 225W. For two cards you could either have one with up to 225W and the other at 75W or both at 150W.

The Mac Pro power supply provides in total a maximum of 980W this is divided between the four PCIe slots, the two PCIe power cables and the rest of the computer e.g. hard drives, DVD drive and the rest of the logic board.

Running two video cards just from their PCIe slot based power is perfectly fine if that is all they need.

This would appear to be the video card Apple are suggesting - Amazon.com: MSI Gaming Radeon RX 560 128-bit 4GB GDRR5 DirectX 12 VR Ready CFX Graphcis Card (RX 560 AERO ITX 4G OC): Co… which is the same as your link.

Looking at the MSI product page here - Specification for Radeon RX 560 AERO ITX 4G OC | Graphics card - The world leader in display performance | MSI Global it says it only needs 60W which is amply covered by the PCIe slot power of 75W.

This card will not support the Mac (pre)boot screen and hence will not support using FileVault, it will however according to Apple's article support installing Mojave.

Hi KidVid! Sorry for the belated response, I didn't see your post until just now. Based on the link to the GPU you provided, it looks like the card is indeed Metal capable and should, in theory, allow you to run Mojave on a "cheese grader" Mac Pro. However, I have not seen any reports of anyone attempting to run two cards, but again, in theory, it should work.

I would buy one to begin with and test to make sure all is well, then buy a second.

Hope it helps!

Geotrax

Hello once again. In theory, there should be no issues with running 3 displays on each card. The PCI-e Power cables are not necessarily to "give the PCI a break" but just to provide more power in general. Graphics cards have become vastly more power efficient over the last 8 years, and the RX-560 is not a power-hungry card. The Dual 5770s you have were mid-range cards at the time, and midrange cards usually require PCI-e power cables.

Hope it helps!

-Geotrax

I wonder if each PCI slot is good for 75 watts?

Yes, that is what I was trying to say. Each (and every) PCI-e slot can provide 75 Watts to its card, independent of all other slot-cards.

The Aux cable provides 12 Volt power. If required, that power helps power the Graphics Processor Unit.

Display data and control signals are much lower that 12 volts, and do not depend on Aux power. To the best of my knowledge, there is no graphics card that is number-of-displays limited by power or any other factors, except for the subtle limit to the number of non-DisplayPort family displays Vs. higher-voltage "legacy" displays I described above.

https://www.macrumors.com/2018/09/24/mojave-2010-2012-mac-pro-metal-graphics-car ds/

Only "Mac-Edition" cards and certain specially-flashed cards will show "Boot screens". So the first screen you will see on such a card will be the login screen (or the desktop if you auto-login).

Modern graphics cards have enough power at appropriate levels to run up to six (in some cases) DisplayPort family displays. To use more than two "legacy" interface displays on a card, you will need some ACTIVE adapters.

HDMI was invented for consumer-quality HDTV, 1920 by 1080p, and using it at anything higher takes special consideration and occasionally special cables, and sometimes it still refuses to perform.

The PCI-e is said to be good for 75 Watts, and each 6-pin Aux cable, if needed, is good for another 75 Watts each. If your card only needs 60 watts, you are good to go with just PCI-e Bus power.

When cards are underpowered, you find out when you stress the card. All the processing units kick in, and the power supply gets overdrawn and the Mac shuts off.