new arm macs with egpu?

[alter_ohm]

today in a live talk about the apple event i heard that it won't be possible to use an egpu with the new mac mini. does somebody know if there is a technical reason for that or is it just the missing drivers for the arm architecture?

thanks alter_ohm

 

[Superhai]

M1 supports PCIe 4 and Thunderbolt, so very likely driver support is the clue. I guess Apple wants people to use Apples own GPU. But we have to wait and see, While the new chip sounds amazing, there is still a gap towards the high end discrete cards.

 

[joevt]

Since the Apple Silicon Macs support Thunderbolt, they must also support PCIe and they must have the drivers for PCIe controllers such as USB, SATA, Ethernet, FireWire, etc.

Every GPU that macOS has a driver for might be usable with Apple Silicon. Apple just needs to recompile the drivers. Do they control the drivers, or does AMD? Check Big Sur. Are the kexts FAT binaries (with x86 and ARM images)?

The GPUs won't be usable during boot since they only have x86 code in their roms (separate BIOS and EFI images). However, any GPU that Apple has a driver for could have a boot time driver created by Apple in the firmware. Doesn't the Mac Pro have AMD boot drivers built into its firmware?

What's the boot environment for Apple Silicon Macs? Is it EFI? The EFI spec was originally created by Intel for Intel PCs. EFI byte code is an option when x86 code cannot be used. I haven't seen a GPU with EFI byte code yet though. I suppose Apple EFI could have an x86 translator. Before there was EFI, there was OpenFirmware. GPUs for Macs back then had OpenFirmware byte code.

 

[Nermal]

What's the boot environment for Apple Silicon Macs? Is it EFI?

It's apparently iBoot (same as an iPhone).

 

[Janichsan]

*deleted*

 

[leman]

today in a live talk about the apple event i heard that it won't be possible to use an egpu with the new mac mini. does somebody know if there is a technical reason for that or is it just the missing drivers for the arm architecture?

Here is my take on this.

Technically, there is no reason why eGPU support would be impossible. This is the question of drivers. However, I don't think we will ever get them. And the reason is software infrastructure.

With M1, Apple is offering unified GPU programming experience and a set of strong guarantees as to which features the GPU will support and how it will behave. It gives developers a very solid and concise base to work with, not to mention some truly revolutionary stuff like unified memory on the consumer desktop. A third-party eGPU would break these guarantees and make mess a mess out of things.

Some additional points to consider:

- very high support cost for a niche feature (drivers need to be written and maintained — it's "included " on Intel Macs, but a separate effort for ARM Macs)
- eGPU is arguably less relevant for the Apple Silicon Macs as the internal GPU with unified memory is likely to be better for content creation anyway and M1 offers more then adequate gaming performance (and no Windows support, with cuts out another large user base)

 

[ww1971]

today in a live talk about the apple event i heard that it won't be possible to use an egpu with the new mac mini. does somebody know if there is a technical reason for that or is it just the missing drivers for the arm architecture?

thanks alter_ohm

no eGPUs will work with Macs with the M1 chip

 

[Superhai]

Here is my take on this.

Technically, there is no reason why eGPU support would be impossible. This is the question of drivers. However, I don't think we will ever get them. And the reason is software infrastructure.

With M1, Apple is offering unified GPU programming experience and a set of strong guarantees as to which features the GPU will support and how it will behave. It gives developers a very solid and concise base to work with, not to mention some truly revolutionary stuff like unified memory on the consumer desktop. A third-party eGPU would break these guarantees and make mess a mess out of things.

Some additional points to consider:

- very high support cost for a niche feature (drivers need to be written and maintained — it's "included " on Intel Macs, but a separate effort for ARM Macs)
- eGPU is arguably less relevant for the Apple Silicon Macs as the internal GPU with unified memory is likely to be better for content creation anyway and M1 offers more then adequate gaming performance (and no Windows support, with cuts out another large user base)

It certainly will be interesting to see. Apple put up PCIe gen 4 as a feature of the M1 alongside thunderbolt. So there have to be a reason.

I don’t expect that graphics card will be able to readily offer support during boot, but it may be possible in the future. However graphics card used as accelerating graphics don’t need that. I think or hope that Apple will offer new graphics drivers, but are not doing it before they finished rewriting the driverkit for the graphics subsystem. Big pro 3D productions uses large scenes with 128, 256 and more GB of textures and models. Unless Apple already have chips in testing with so much memory on the chip, as well as even more powerful graphics processing, I think we will see support for external graphics. But driverkit is still not complete, so that will not happen with this round, so maybe in next version of MacOS.

 

[Emanuel Rodriguez]

Since the Apple Silicon Macs support Thunderbolt, they must also support PCIe and they must have the drivers for PCIe controllers such as USB, SATA, Ethernet, FireWire, etc.

Every GPU that macOS has a driver for might be usable with Apple Silicon. Apple just needs to recompile the drivers. Do they control the drivers, or does AMD? Check Big Sur. Are the kexts FAT binaries (with x86 and ARM images)?

The GPUs won't be usable during boot since they only have x86 code in their roms (separate BIOS and EFI images). However, any GPU that Apple has a driver for could have a boot time driver created by Apple in the firmware. Doesn't the Mac Pro have AMD boot drivers built into its firmware?

What's the boot environment for Apple Silicon Macs? Is it EFI? The EFI spec was originally created by Intel for Intel PCs. EFI byte code is an option when x86 code cannot be used. I haven't seen a GPU with EFI byte code yet though. I suppose Apple EFI could have an x86 translator. Before there was EFI, there was OpenFirmware. GPUs for Macs back then had OpenFirmware byte code.

I checked, and the kexts for all AMD GPUs are x86_64, non-fat (I'm running an ARM Mac mini). Seems to me to be the likely reason that eGPUs aren't supported. Non-Apple GPUs are currently not supported in any form on ARM. I suspect we'll need to wait for higher-end Macs to see AMD GPU support, and then we may see eGPU support as well.