Hi,
Having multiple GPUs connected to a Thunderbolt hub can be useful for certain use cases, such as data processing or machine learning tasks that can be parallelized and distributed across multiple GPUs. However, as you mentioned, the limited PCIe bandwidth may be a bottleneck for some workloads.
In terms of your results, a speedup of 0.77 and 0.43 for 2 and 3 GPUs, respectively, compared to a single GPU is a good improvement. However, the performance gain may vary depending on the specific workload and how well it can be parallelized across multiple GPUs.
Regarding the RTX 6000 GPUs, they are high-end GPUs designed for professional applications such as scientific computing and machine learning. They have a higher memory bandwidth and more CUDA cores than the GTX 1060, so they may provide even better performance gains when used in a multi-GPU setup. However, they are also more expensive, so it may not be practical for everyone to use them.
