Mac Pro 1,1 and Sapphire HD 7970

[Charlee78]

Hi guys, I've upgraded my old Mac Pro tonight but I cannot get it to boot. It has the 2,1 firmware and running El Cap on a new SSD. Everything was working great with the old HD 5770 when I powered the rig down. I did the pixlas mod and I rechecked the pinout twice with a multimeter to make sure I did it right. I am plugging via HDMI and going thru DVI with an adapter did nothing. Do I need to buy a display port to HDMI adapter?

 

[Charlee78]

Little update, when I put back the HD5770 in the 1st slot and the HD7970 in the 3rd one I can use it if I first boot with the old one and then switch the HDMI cable. If I reverse them it doesn't see the old card. Can I use the HD7970 in the 3rd slot without loosing performance?

 

[MIKX]

I recommend getting a cM 4,1 and then upgrade it to 5,1 .. or . . lash out & get a later model 5,1.

I had a 2,1 running Mavericks 9.5 but it was so power hungry, the 4,1 & 5,1's have much better power management.

I'm using a Sapphire Dual-X 3gb 7970 ( efi flashed & @ 5GTs ) in both High Sierra & Mojave.

The performance difference is profound

Your problem may be solely related to what the 1,1 can handle & OS X limitations.

Please check out my .sig below.

I can't really help you out with cMP 1,1 problems but I'm sure that someone here will have a solution.

Good luck.

 

[Charlee78]

The idea is to keep the 1,1 for 2 or 3 more years. But then I will be buying a 5,1 for sure.

By the way, what is 5GTs?

 

[MIKX]

The idea is to keep the 1,1 for 2 or 3 more years. But then I will be buying a 5,1 for sure.

By the way, what is 5GTs?

The PCIe LINK Speed of the 7970 . Until recently non-Apple cards ran at 2.5 GT/S. On my 7970 I had to remove a resistor.

LINK : Post #199
https://forums.macrumors.com/thread...-and-nvidia-card.1547340/page-8#post-24856990

I use X-Plane 11 a lot, this mod definitely improved performance in the flight sim.


Go to "About this Mac" then "System Report" and look at your GPU in " PCI ".

 

[Charlee78]

Okay, thanks for the info. system report give me an error when I go to the pci. I did some research and I think I'm gonna try the card the way it is for now. It's already a big improvement from the HD5770 that I had in it.

I'm pretty sure the HD7970 will be good enough for photoshop right? Because that's the main thing this rig will do, processing and editing pictures and videos sometimes.