Thunderbolt 4

[RobertJasiek]

The speed of Thunderbolt 4 is up to 40 Gb/s = 5 GB/s.

Thunderbolt 4 via PCIe is up to 32 Gb/s = 4 GB/s.

(b = bit, B = Byte)

I wonder whether it is fast enough for eGPUs and AI programs, such as KataGo.

For comparison,

Code: Select all

PCIe 3.0  8x =                7,9 GB/s
PCIe 3.0 16x = PCIe 4.0 8x = 15,8 GB/s
PCIe 4.0 16x = PCIe 5.0 8x = 31,5 GB/s
PCIe 5.0 16x =               63,0 GB/s

[Ruarl]

Is the bus bandwidth a limiting factor for Go engines? You can certainly get eGPUs on Thunderbolt 3 which are capable of moving 25fps ish 4k ish video over the bus. If you had a GPU-only implementation of a Go engine it would only need to be receive the board state, and then later return the co-ordinates of its move, which is far less data.

Since you're asking, I guess there's lots of CPU <-> GPU communication as the AI decides its move? How do they work?