Can you please tell me what are you guys talking about? I'm a bit lost.
Why is PCIE4 or 5 important and what is limitation in TB3? You can already connect an external screen and it can drive XDR so what is this "fuss" about the PCIE and TB, please?
Thank you so much. So yeah, its essentially bandwidth on those protocols. I was just confused why you guys talked a lot about eGPU and I guess that is what derailed me.
So basically, if one doesn't care about eGPU then the bandwidth we get now should be sufficient for RDNA2 (if we are lucky) and anything else? Or we will still get slow ins?
I apologize that I disappeared for a long time without answering the question - I’m stuck on a Mac Pro forum thread. When you go there, you feel like you got on board to Major Tom
The problems of TB3 and PCI-e 3 as such do not exist right now, but this is only today. If you buy a hypothetical iMac 2020 today, then in the future you will encounter the problem of expanding power by eGPU through TB3. TB3 was a great solution at its launch, it is a good solution today. But in a few years, the capacities of the built-in GPU accelerators have improved well and in order to get a noticeable increase even more, you need to install much more powerful videocards in the eGPU box. Here you will encounter the problem of insufficient TB3 bandwidth.
I will give a distant, not a direct example, but the point is that your conditional Vega 56, which is built into the iMac, will be more productive than Vega 64, which is connected via eGPU. This is because:
1. The video card soldered into the motherboard has a higher communication speed than TB3
2. Your information goes a double way: from the processor to the eGPU and back to the built-in monitor (unless you use an external monitor, this is a little easier)
Therefore, I said earlier that the farther the time goes, the less sense exists in eGPU if they are used on initially powerful iMac configurations. The next generation TB with a doubled data rate could solve this problem, but the next 4th generation of Thunderbolt is not going to become faster, so we will have to wait for the 5th, which will probably not be very soon.
The same problem with PCI-e 4. It is already in operation today and I think that most of the new videcards will switch to it very quickly. Therefore, the PCI-E 4 speed potential will be even more difficult to transmit via TB3.
A small remark. The problem with PCI-e now is not so serious for the reason that the current even powerful GPUs still have not run into the limitations of PCI-e 3.