Performance Drop on TB3 with External 8K VR?
Any performance drop with TB3 eGPU setup is coming from the bottleneck of PCIe connected to TB3 controller.
The communications through PCIe on eGPU system are mostly due to Host to Device/Device to Host communication, like update VRAM.
Updating VRAM is due to such things like updates of model status like moving of characters, and processed in between each complete frame to accept new changes or user inputs.
So if you get 144fps, CPU updates such VRAM info 144 time per sec. and this requires (total VRAM memory)*144/s of PCIe bandwidth.
This means the performance hit due to TB3 bandwidth limit are bigger as the frame rates goes high, so lower the resolution, higher the bottleneck.
So, what if we use 8K display like Pimax 8K?
Pimax 8K uses two 4K displays, and it means, in theory of parallel processing, it takes about 8 times more of the processing time when using FHD display.
The expected frame rates will 8 times less than FHD's one, and expected occupation of PCIe bandwidth also.
So, IN THEORY, TB3 eGPU system can perform same as desktop with full lane PCIe and competitive CPU.
How do you guys think about this?