Thunderbolt is royalty-free; does AMD have any implementations available?

Incorrect.

Intel did announce in 2017 they planned to release thunderbolt royalty free in the future; however, they still have not released it as of yet. And given their new competition from AMD - I doubt they plan to now anytime soon

It seems like it's not so binary and it's more like kinda royalty free: https://arstechnica.com/gadgets/2019/03/thunderbolt-3-become...

They gave it away to usb form but maybe they won't for anything AMD wants to do?

It's called "USB 4" now. And yeah, a few years away at best.

USB4 Final Spec 1.0 should be ready anytime soon. It was originally scheduled for mid 2019, but you can defiantly expect the draft before year end and product ready by next year.

There is at least one motherboard that I know of with Thunderbolt on it for AMD processors, the X570 Taichi. It does have some limitations though.

What are the limitations you're on about? I'm in the market for Ryzen 3900X + X570 + TB3.

Wake issues with some devices, external GPU solutions do not work.

Will external GPUs never work? As in, physically impossible? That'd be my main purpose.

Physically impossible, no, but external GPUs definitely work right now with Intel processors but even they have their limitations related to usability moreso than technical issues. I have one now with a 1080 Ti off of an Intel NUC and not being able to see my BIOS without switching to the iGPU can be cumbersome when troubleshooting. Once in a while when I reboot (this is very frequent actually because my eGPU's PSU's power limiter cuts out if I forget to throttle the power usage) the GPU doesn't come back unless I hard cycle a couple times.

The annoyances are such that I'm waiting for a 3900X to be available in-store so I can build my full workstation finally after sitting on a NUC + eGPU setup for over a year.

I don't want to buy Intel CPUs, nor Nvidia GPUs. Exception being an Nvidia Shield.

You'll be going for 3900X + X570 Taichi? Or another board? Ideally I'd also want ECC RAM.

I got a 3900X and the Asus X570 workstation board to make sure I'd be able to support ECC RAM within basically a couple hours after I made that post. My needs are video encoding and virtualization setups needing lots of cores so this makes a lot more sense for me than any comparable Intel setup for my money. I'm slightly cheaping out by not going with ECC RAM but in the era of catering to overclocking gamers over professionals I'd rather pay more for a workstation board.

Does the X570 support ECC RAM?

ECC support is built into the IMC (on the CPU) so de facto, every single Zen chip (except the non-PRO APUs) usually have support, but official support is still on a per motherboard basis (and you'd probably want to check the memory QVL as well) if it's important for you (it was for me) so it's best to check each board model's specs.

The Asrock X570 board mentioned definitely has support, as do the other high-end X570s I looked at like the Aorus Master, Asus C8H, Pro WS, etc.

Based on X570 BIOS updates so far (and their overkill VRMs this gen), I think the Gigabyte/Aorus boards would be my pick atm (I went w/ a C8H and I'm somewhat unhappy w/ the CPU/memory voltage wonkiness when tweak, but it does give me 30 IOMMU groups, so I'm able to do GPU passthrough via VFIO to a Windows VM w/o any issues).

Thanks for the information. Does GPU passthrough to Windows allow high-end gaming from Linux (running a windows VM)? What specs would I need to look for in a motherboard to support that?

Yes, although it's not entirely straightforward and there are many sharp edges, so it's maybe not for the faint of heart. Since I just did it, here's a guide I wrote up with my specific hardware and some of the issues I've encountered to set up my system specifically for VR passthrough: https://forum.level1techs.com/t/zen2-ryzen-3700x-and-x570-as...

Note: I haven't dealt with sound yet, which is another potential sticking point if you're doing gaming (most people seem to use a separate sound device, although I've seen some people use network sound when running into issues; HDMI sound I assume would work fine if you're doing GPU pass through) since I was just focused on getting my VR HMD working, which has it's own sound output already.

IOMMU groups are defined by AGESA and the X570 boards in general seem to have much finer grained groupings vs earlier AMD chips/boards (although people seem to have done ACS workarounds). My recommendation is to find something that someone has gotten working already and just follow along (the VFIO subgroup at level1techs and r/VFIO on reddit seem to be the best resources).

Yes, that works. The motherboard doesn't need to do anything special so any should work, unless they did something silly like forget to put the IOV toggle in BIOS.

Caveats:

- Anti-cheat systems used in multiplayer games generally don't like running in VMs. - Consumer Nvidia cards don't get reset on VM reboot, you need to reboot the machine. - IIRC Nvidia cards need a KVM hack to get the driver to work.

Actually, it's AMD Vega cards that have a PCI reset issue that doesn't work well with VM cycling. There's a new kernel patch just the other week that fixes this: https://forum.level1techs.com/t/vega-10-and-12-reset-applica...

Nvidia cards do require a config workaround for VM detection but the workaround is relatively straightforward (and works w/o further mucking).

>Still surprises me the new Mac Pro isn’t AMD.

Yes, I was rather hoping for some surprise, with 2 Socket, 128 Core Max Mac Pro. I guess Apple has to keep Intel happy until they get their hands on Intel's modem unit.