1

I’m using a MacBook Air (early 2015) and trying to do some 3D rendering however it’s an absolute pain to do it on the cpu and it’s probably not good for the laptop to run at those temperatures for that long anyway.

I was thinking of getting an eGPU. The Apple website says that I need a MacBook with an intel processor and a thunderbolt 3 port. Mine doesn’t have the latter but I do think that USB to thunderbolt 3 adapters exist, would an eGPU still work if I were to use an adapter like that?

Is there nothing else I can do to speed up my rendering?

3
  • What rendering engine do you use?
    – bmike
    Sep 6 at 14:14
  • @bmike I use cycles Sep 7 at 15:04
  • 1
    I’ve edited the “no”. You will want to render on another OS or hardware if the current performance isn’t where you can afford the time or cost of delay.
    – bmike
    Sep 7 at 19:17

3 Answers 3

3

No, because USB ≠ Thunderbolt (TB) 3. The USB specifications (unless its USB 4, which didn't exit in 2015) were always inferior to TB. In order to use an eGPU you need to transfer data at very high speeds. While TB 3 already supported up to 40Gbps the USB ports on your machine only allow 5Gbps. This is simply too little for an eGPU (apart from the fact that the protocol is also different...).

The only GPU hardware supported on macOS are Metal for Apple Silicon and AMD per your render engine of choice, cycles.

Metal is supported on Apple computers with Apple Silicon or AMD graphics cards. macOS 12.2 is required to use Metal with Apple Silicon while macOS 12.3 is required to use Metal with AMD graphics cards.

2
  • Oh.. that sucks. Is there nothing I can do to speed up my rendering then? Sep 2 at 6:57
  • @pythonnewbie See my answer.
    – benwiggy
    Sep 2 at 7:36
3

Is there nothing else I can do to speed up my rendering?

Short of a new machine, no. 3D rendering is very hard work, and has always required top-of-the-line hardware. This is why desktop Mac Pros with dual GPUs exist. (I'm not saying you need to buy one of the insanely expensive ones, but companies are prepared to pay those prices because time is money.)

A MacBook Air is designed and marketed for 'light-to-moderate' use; and the MacBook Pro name indicates more capable hardware for professional-level work, like video, software development and animation. An Air wasn't the right tool, even in 2015! ;-)

If you're doing this commercially, then I'd suggest investing in a new M1 Pro or Max MBP. The GPU capabilities of those Macs holds up well against current desktop GPUs, and the overall performance is absurdly fast.

If you're doing this as a hobby, and can't afford to spring for a new MBP, then I'm afraid you'll just have to let it run. It will get hot, but the fans are designed to cool things down, and the CPU will also slow down as it gets hotter; in extremis the CPU will shut itself off to prevent heat damage if things get out of control. However, you'll be 'pushing the envelope', and something might possible 'give', if you are doing this a lot.

In the old days, people would leave these sorts of tasks running overnight!

One more thing: Apple's laptops between 2015 and the current M1s are 'not great' for a variety of reasons, mostly involving heat, GPUs and bad keyboards, so I wouldn't buy a second-hand Mac laptop in that range either.

6
  • Oh, Well I suppose I’ll just try out a render farm or something for now. I do intend to get a new computer a year from now for college and was hoping I’d get something more sturdy that’ll last me a while and that’ll let me do rendering and animation, do you think a desktop Mac would be significantly better than a MBP in that case? Or would an mbp be able to handle it just fine too? Also, Thank you for the answer! Sep 2 at 7:54
  • @pythonnewbie Apple's desktop Macs now use exactly the same M1 (or M2) CPU family as the laptops. The Mac Studio has a monster 'Ultra' CPU that's not in any laptop, but the M1 Max is in the lower-end Mac Studio and the top-end MBP -- and that should be good enough. New Macs are forecast to be released later this year, so keep an eye out on the news.
    – benwiggy
    Sep 2 at 8:03
  • alright, thanks a lot! I really hope they add eGPU support in the new ones Sep 2 at 11:07
  • 2
    @pythonnewbie Seriously, take a look at the graphics benchmarks of the M1 Max.
    – benwiggy
    Sep 2 at 11:34
  • 1
    @pythonnewbie you should definitely first consider the software you use and your actual workload in order to make an informed decision. While the M1 and also M2 Macs show incredible performance (especially per Watts), you still may be better off buying a Windows PC/Laptop with a dedicated NVIDIA or AMD GPU. For example, Blender (not sure if the problem is still as severe) had big optimization problems in the beginning (since the Apple M chips use a new architecture), so performance wasn't very good.
    – X_841
    Sep 3 at 7:41
2

Thunderbolt 3 is not strictly required for an eGPU to work. The people that sell and support them will tell you Thunderbolt 3 is required because if used with Thunderbolt 2 it might not perform as quickly as expected. To connect a Thunderbolt 3 device to a Thunderbolt 2 computer will require a Thunderbolt 2 to Thunderbolt 3 adapter. I have done this to connect a Thunderbolt 3 dock to a Thunderbolt 2 Mac and it works as intended, but the data throughput is limited to that of the Thunderbolt 2. The Thunderbolt 3 adapter makes a physical connection possible, it doesn't make the connection faster.

Connecting a Thunderbolt device to a USB port is not likely to work. There's a protocol difference that would take drivers to fix, and I doubt anyone is going to write drivers. Thunderbolt 2 and Thunderbolt 3 are essentially the same protocol so no special drivers needed, but Thunderbolt 2 is going to be half the speed of Thunderbolt 3. Depending on the application and expectations using Thunderbolt 2 may work.

The issue of Apple silicon Macs not supporting eGPUs is also a matter of drivers. There's no inherent reason any eGPU can't work with Apple silicon, it is just that nobody has written drivers yet. I've seen on Linus Tech Tips where they experimented with an Ethernet based eGPU and got that to work with Apple silicon Macs. Why an Ethernet connection to an eGPU works but not one by Thunderbolt gets complicated really quick. I'm a bit surprised it worked but after some thought I can see why it does.

A Thunderbolt 3 based eGPU should work fine on Thunderbolt 2 with an adapter, for some definition of "fine". If I'm mistaken on your model of MacBook having a Thunderbolt port then that's not an option. Ethernet based eGPUs are an option if the software supports that, and like with Thunderbolt 2 vs. Thunderbolt 3 there's going to be a performance bottleneck because Ethernet isn't as big of a data pipe. There's really no easy way around the speed limits of the ports out of the computer, but you should be able to get the computer to talk to a GPU. If this is worth the effort vs. just getting a new computer is up to you.

1
  • wait you're saying that a thunderbolt 3 GPU can work,with thunderbolt 2 (just slower)?? I've never heard of this. I'm gonna check out that Linus text tips video you mentioned. thanks a lot! Sep 7 at 15:08

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .