As you can see, I'm in the unfinished garage, so this will be a short episode of the Definitive
Mac Pro upgrade guide.
I'm going to talk about GPUs.
Specifically, the Radeon GPU is made by AMD and the compatibility as it pertains to the
classic Mac Pros and the 2019 Mac Pros.
It should not come as any surprise that in 11.4, Apple introduced GPU support for the
AMD Big Navi or Navi 21 GPUs.
This did not include the Navi 22, which is the 6700 and 6700 XT series GPUs.
Those are not supported under macOS.
macOS ships the drivers as part of the OS, so unfortunately, if you're running an older
OS, you have to upgrade.
This was the big hang-up for the classic Mac Pros as the classic Mac Pros had a huge problem
in 11.3.
There was a race condition, the race condition, which introduced a bug that would crash at
boot frequently and sometimes corrupt your boot drive.
This was bad, as you can imagine.
So what happened is the community rallied, mostly one developer by the name of Syncretic,
introduced latebloom, a Band-Aid fix, and later a full-blown patch as known as Surplus.
Get it Sur-plus?
Anyhow, puns aside, Surplus was the savior for the classic Mac Pros as it enabled the
latest and greatest support, The point where you could potentially use the latest GPUs
in your classic MacPro, right?
Well, not that easy.
Unfortunately, the GPUs are not supported by the classic macros.
In fact, if you stick one in, you can't even boot.
You can't get to Linux.
You can't get to Windows, and you certainly can't get a macOS.
This is because of the EFI ROM on the card, and I'm just going to read the research done
by the guy who discovered this, Petri Krohn because I think it's very interesting, so
let me just read the post, and I'll put it on screen as I do it.
Petri, please correct me if I said your name wrong.
I downloaded this VBIOS file from TechPowerUp.
It is for the reference design RX 6800.
I opened it in Hex Fiend.
It contains two EFI sections, both labeled "GOP AMD REV: 000.000.000.020.001 2182337
537937".
I then opened the VBIOS file in Hopper Disassembler 4 and searched for "MXM" and "YMM".
There are multiple instances of AVX calls in both the EFI sections.
The legacy BIOS section only contains references to the 128-bit XMM registers, so it should
execute in older processors with the SSSE instruction set.
To translate that back to English, this is because the EFI ROM contains AVX instructions.
These are CPU instructions that are not found on the classic Mac Pro CPUs, which is a problem.
This causes the computer not even to be able to boot.
You are asking the CPU to do things it doesn't know how to do.
Now the interesting part is the second part as the legacy ROM that's used for BIOS for
older PCs that do not use EFI does not contain the AVX CPU instructions set.
This is promising.
This is because if you were to hack the GPU ROM, perhaps maybe, and this is a big maybe,
you can get it to boot and then be able to load the drivers under macOS.
Then you'd be able to use the GPU. that requires some ROM hack in, and we have seen from hacks
as in the form of MacVIdCards.
that dude was able to hack in EFI support to the GPUs and make them able to work under
macOS and display the boot screens.
Now would this happen with these cards?
I don't know.
These are very expensive cards to throw in such old computers.
The Mac Pro 2010 was released in 2010, and that's almost 12 years ago.
As a recording, this.
So maybe when you're watching this, this has changed.
But, I'm going to guess probably not.
Just maybe, we'll see someone hacking a ROM to support macOS either in the form of removing
the EFI ROM (from the GPU), forcing it to the BIOS, or splicing them together.
So there is hope for us.
Now to the 2019 Mac Pros and same GPUs, and this does also pertain to the class Mac Pro.
The 2019 Mac Pro can support a GPU that's up to 30 cm long or 30.5 cm, to be exact.
Unfortunately, some of the AMD GPUs get really long with their aftermarket coolers.
The reference designs of these GPUs will fit in a 2019 Mac Pro, but some others won't.
I'm going to link a blog post about a guy who discovered this the hard way and his inevitable
resolution of getting the right GPU for his Mac Pro.
It worked out for him.
this is where I got the information, and I found that very interesting.
30.5 cm into dumb-dumb imperial is about 12 inches on the nose.
That's all the longer of a GPU.
You can stick it into your 2019 Mac Pro.
I don't have a classic on me right now to measure, but you should be able to do that
with a tape measure and figure out how long of a GPU is when in the future you encounter
a GPU that might not fit into your classic Mac Pr.
If that is the case, you're living in a better timeline, in a better world, where are you
these GPUs in your classic mac pro, and it's not totally insane to pay the money to get
one or stick to your classic Mac Pro.
I want to be on your timeline if you're out there.
If you're looking for GPU advice for your classic Mac Pros, I have an entire episode
dedicated to GPU upgrades for the classic Mac pros.
It has the best GPUs you can get for it.
You can find the link for that in the description of this video.
And, it seems like this is a good place as any to wrap up this video.
I will edit it while I consume this wonderful beer from Fremont.
Thanks for watching.