MP 1,1-5,1 Success: RX-6800XT in cMP 4,1/5,1

[tsialex]

I know the The 6600 and 6600 XT can be flashed and used without the pixlas mod. Not sure if that has changed with the RX 6800, RX 6800 XT, RX 6900, RX 6900 XT in that they still require the power using the mod.

GPU power draw and physical size have nothing to do with the firmware patching process to make the GPU firmware compatible with a MacPro5,1. If the GPU requires more power than what the backplane can provide, Pixla's mod will be needed.

The most powerful NAVI 2x GPU that works without a Pixla's mod is the RX 6600XT, anything else will need more power than the backplane can provide.

So looking at gpu options to keep this decade old monster going. I do not game btw but more so into Adobe products. I did get the M1 ultra and also the M2 ulgra to test them out from a friend when they were released but kept holding off and going back to my Mac pro 5.1 since the cost of the Ms were astronomical.

Maybe you gonna need to re-think this. Since a month or so, several Adobe products started to require AVX 2 and do not run with a MacPro5,1 anymore.

Since Sonoma does not support processors without AVX 2, apps are now being compiled with AVX 2 instructions and more and more apps will not run with a MacPro5,1.

 

[cpnotebook80]

Ah good to know about the Adobe products then. Thanks for the clarification and update. Will keep any eye on the adobe updates also since for now its fine on monterey and my gpu for the tasks i throw at it.

 

[Valdaquendë]

Thanks for that alert, tsialex. The shakedown for Adobe (Mac) products is this:

Adobe will update system requirements with the next major release (v. 24.0) of their video applications to include AVX2, which the legacy Intel Xeon processors do not have. This includes the 24.0 versions of Premiere Pro, After Effects, Audition, Character Animator, and Media Encoder. there is no clear statement about if or when other Adobe CC apps may upgrade their CPU requirements.

In late 2023, 24.x versions of Premiere Pro, After Effects, and Media Encoder will no longer support NVIDIA Kepler series graphics cards, from the GT 630 through the GTX Titan Black.

This is disheartening but, of course, inevitable and has me leaning in the direction of the MP2019. I have a deep and abiding affection for my cMPs ...

 

[avro707]

Ah good to know about the Adobe products then. Thanks for the clarification and update. Will keep any eye on the adobe updates also since for now its fine on monterey and my gpu for the tasks i throw at it.

Some of the newest versions of the Adobe products have now just started to need AVX2 - I found that on my 6,1 Mac Pro with the updates that came this week.

 

[MacINCheez]

I posted this in the 6800XT/6900XT thread, but I feel like it's not getting the visibility it deserves, so I'm posting in the main forum, so that people can see that the cMP is STILL going strong, now with the addition of AMD's 6k series cards, all thanks to Syncretic.

I am more than happy to report that @Syncretic 's patch does work 100% to install an RX-6800XT on a cMP 4,1>5,1 running OpenCore 0.8.0, Big Sur 11.6.5, the rest of my specs are in my sig. (@Greggant, if you wanna mention this confirmation on the DMUG youtube, gimme a shoutout! )

As soon as Syncretic made his post, I returned my RX-5700XT and acquired a brand new RX-6800XT.

Whilte I waited for the 6800XT to arrive, I went back to my XFX RX-580, so you will see before and after pics below. Since I had previously already done the Pixlas mod for the 5700XT, it was a simple plug and play.


Here you go folks, as promised, the excitement!:
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The day I installed it (May 1st), I ran some quick benchmarks:
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I made a GB5 account a few days later, so here are more results:

MacPro5,1 - Geekbench

Benchmark results for a MacPro5,1 with an Intel Xeon X5690 processor.

browser.geekbench.com

MacPro5,1 - Geekbench

Benchmark results for a MacPro5,1 with an Intel Xeon X5690 processor.

browser.geekbench.com

And of course Windows:

Apple Inc. MacPro5,1 - Geekbench

Benchmark results for an Apple Inc. MacPro5,1 with an Intel Xeon X5690 processor.

browser.geekbench.com

Apple Inc. MacPro5,1 - Geekbench

Benchmark results for an Apple Inc. MacPro5,1 with an Intel Xeon X5690 processor.

browser.geekbench.com

As you can see from the various benchmarks, the cMP now easily DECIMATES the 20-core Ultra Mac Studio in terms of graphics processing power. Just had to put that out there as I'm tired of reading BS posts from iSheep around that.

I ran a bunch of different benchmarks in the 6800XT thread, so if you're interested in that, take a look beginning on page 39.

Again, just wanted to put this here, so that it gets the visibility that it deserves. This proves that, thanks to the brilliant work by members of this community, our cMP's are STILL very powerful and capable machines, even 12 years down the line. I want to thank you guys, especially Syncretic, and the OpenCore team for keeping this very capable machine, still purring like a kitten!


Cheers!

Great News ! But unfortunately it`s not applicable for people like me who do not possess a PC

 

[Valdaquendë]

Great News ! But unfortunately it`s not applicable for people like me who do not possess a PC

Perhaps I'm missing something but this seems an odd response.

If you're saying that you don't have a PC (as in "Windows machine") but you DO have a classic Mac Pro (MacPro4,1 or MacPro5,1, commonly referred to as "cMP"s), the above remarks address those models and are, therefore, quite applicable.

If you do not own a cMP but do have a Windows PC that you're running MacOS on (a "Hackintosh") or if you don't own a PC (as in "personal computer of any kind"), this information is, indeed, inapplicable ... but one wonders why you responded to that post.

 

[MacINCheez]

Perhaps I'm missing something but this seems an odd response.

If you're saying that you don't have a PC (as in "Windows machine") but you DO have a classic Mac Pro (MacPro4,1 or MacPro5,1, commonly referred to as "cMP"s), the above remarks address those models and are, therefore, quite applicable.

If you do not own a cMP but do have a Windows PC that you're running MacOS on (a "Hackintosh") or if you don't own a PC (as in "personal computer of any kind"), this information is, indeed, inapplicable ... but one wonders why you responded to that post.

I have an old Mac pro 5.1 but no infomation how to flash the GPU using the latter..hence my response...ppl who do not possess a pc running windows wouldn`t be able to perform that crucial task

 

[tsialex]

I have an old Mac pro 5.1 but no infomation how to flash the GPU using the latter..

Simply, it's not possible to do it with a MacPro5,1. A NAVI 2x GPU will block the Mac Pro power up process until flashed.

hence my response...ppl who do not possess a pc running windows wouldn`t be able to perform that crucial task

Buy a SPI flash programmer and flash the GPU SPI instead. If you can't or don't want do it yourself, ask a friend or pay someone to do it.

 

[startergo]

and flash the GPU SPI instead

Alex, where exactly is the chip?

https://www.techpowerup.com/review/amd-radeon-rx-6800-xt/images/front_full.jpg

https://www.techpowerup.com/review/amd-radeon-rx-6800-xt/images/back_full.jpg

 

[MacINCheez]

Simply, it's not possible to do it with a MacPro5,1. A NAVI 2x GPU will block the Mac Pro power up process until flashed.



Buy a SPI flash programmer and flash the GPU SPI instead. If you can't or don't want do it yourself, ask a friend or pay someone to do it.

ohh..thanks for this useful information..you`ve given me hope again.

 

[tsialex]

Alex, where exactly is the chip?

https://www.techpowerup.com/review/amd-radeon-rx-6800-xt/images/front_full.jpg

https://www.techpowerup.com/review/amd-radeon-rx-6800-xt/images/back_full.jpg

U3, PCB front side, left to the GPU chip, it's the GD 25Q80C 8-pin SOIC SPI flash.

 

[MacINCheez]

GPU power draw and physical size have nothing to do with the firmware patching process to make the GPU firmware compatible with a MacPro5,1. If the GPU requires more power than what the backplane can provide, Pixla's mod will be needed.

The most powerful NAVI 2x GPU that works without a Pixla's mod is the RX 6600XT, anything else will need more power than the backplane can provide.



Maybe you gonna need to re-think this. Since a month or so, several Adobe products started to require AVX 2 and do not run with a MacPro5,1 anymore.

Since Sonoma does not support processors without AVX 2, apps are now being compiled with AVX 2 instructions and more and more apps will not run with a MacPro5,1.

Hey bro..do you think i can patch an AMD RADEON RX6650XT OC edition or where can i find information about patching this card and use it in an old mac 5.1..any information will be very much appreciated. Thanks

 

[tsialex]

Hey bro..do you think i can patch an AMD RADEON RX6650XT OC edition or where can i find information about patching this card and use it in an old mac 5.1..any information will be very much appreciated. Thanks

Several people successfully patched the RX 6x50 cards with the RX 6x00 firmwares, use the search/read the threads and learn what you need to do.

 

[Valdaquendë]

MacINCheez, sorry. Had I back-trailed the thread, I would have understood.

I took tsialex's advice about using an SPI flasher when I was restoring/upgrading a couple of cMPs back in 2022; I recommend it. The flasher was less than $10 and learning to understand and use it afforded me an hour or so of geeky pleasure that has enabled me to flash one GPU and restore a non-functional cMP backplane to usefulness. Not a skill one needs often but VERY handy when it is called for.

If that is not to your taste, see if there is a tech in your area that will do the job. It's about a half-hour job; at my shop rate that would be about $30. Or, as Alex suggested, find a friend who will let you use his/her PC long enough to mod your gpu's spi.

Best of luck!

 

[Balbuzard2A]

Really interesting topic. May be it is time for me to jump to

XFX Speedster MERC319 AMD Radeon RX 6800 XT Core instead of 5700xt.... Has anyone tested with an xfx one ?​

 

[superlativo]

I have a Mac Pro 4.1 > 5.1 with an Asus Strig RX 560 4GB. I found a second-hand Asus TUF RX 6800 XT 16 GB at a good price at the same as a Sapphire RX 6800 (not XT). I know that non-XT models do not need the Pixlas Mod cable.

I wonder if the Pixals Mod cable is sold on Aliexpress or Ebay. I have found several ads for the cable for Vega 64 but not for the RX 6800 XT. So it makes me sad to think that the only option is to do it directly on the Mac Pro. I don't see myself qualified to do that job, which is excellently explained in the The House of Moth tutorial. If I can't buy the cable I will have to buy an RX 6800 (not XT).

Thanks in advance.

 

[EconDork]

It takes up 3 slots on the cMP:

View attachment 2002141

I used to have an SSD sitting in an OWC PCIe adapter sitting in Slot 4, but I moved it into the SATA bays, and moved my bluetooth/wifi antennas up a notch, as you see in the pic.

I have a Dell OEM 6800XT installed in 2 slots , it's snug but you can use both 16X PCIE. My M2 Max with only 64gb ram crushes it though for rendering video /exporting in Resolve or Premiere despite what the GeekBench scores say. Mine also score very high

 

[EconDork]

I have a Mac Pro 4.1 > 5.1 with an Asus Strig RX 560 4GB. I found a second-hand Asus TUF RX 6800 XT 16 GB at a good price at the same as a Sapphire RX 6800 (not XT). I know that non-XT models do not need the Pixlas Mod cable.

I wonder if the Pixals Mod cable is sold on Aliexpress or Ebay. I have found several ads for the cable for Vega 64 but not for the RX 6800 XT. So it makes me sad to think that the only option is to do it directly on the Mac Pro. I don't see myself qualified to do that job, which is excellently explained in the The House of Moth tutorial. If I can't buy the cable I will have to buy an RX 6800 (not XT).

Thanks in advance.

It's not a simple cable unfortunately ..it's a modification. If you're in Los Angeles I can refer you to someone who is very good at such modifications.

 

[EconDork]

It's not a simple cable unfortunately ..it's a modification. If you're in Los Angeles I can refer you to someone who is very good at such modifications.

that's with the only true 2-slot 6800xt I am aware of (DELL OEM 6800XT) you can find them on eBay, they were in certain Alienware desktops

 

[startergo]

I wonder if the Pixals Mod cable is sold on Aliexpress or Ebay.

I used this one:

Mac Pro Pixlas Mod Open-End to Dual (6+2) Pin Power Cable (Splice Connectors Available)

Mac Pro Pixlas Mod Open-End to Dual (6+2) Pin Sleeved Cable

kareonkables.com

 

[superlativo]

I used this one:

Mac Pro Pixlas Mod Open-End to Dual (6+2) Pin Power Cable (Splice Connectors Available)

Mac Pro Pixlas Mod Open-End to Dual (6+2) Pin Sleeved Cable

kareonkables.com

Thank you very much for the link but that cable is not plug and play. I see that one of the ends is a group of cables that requires work on my part that I don't know how to do.

 

[superlativo]

It's not a simple cable unfortunately ..it's a modification. If you're in Los Angeles I can refer you to someone who is very good at such modifications.

I live very far from Los Angeles. Also thank you very much for the offer. I have found videos on YouTube on how to make the Pixlas Mod. I will see if I dare to do it. The most I have done is disassemble a Powerbook G4 to change the HDD for an SSD and the same to an old Mac Mini. If I don't see myself capable, I will buy an RX 6800. Thank you very much EconDork.

 

[startergo]

I see that one of the ends is a group of cables that requires work on my part that I don't know how to do.

It is all explained in the pictures. It is also in the Pixlas thread. By the way I don't think this is the correct thread for this question.