MP 7,1 2x W6800X vs 1x W6800X Duo?

[bniu]

I'm curious what the performance difference between having two W6800X cards vs a single W6800X Duo are?

The two W6800X card option on apple is $600 more than the single W6800X Duo option.

Total GPU memory would be the same, total of 64GB GDDR6 VRAM. Does having two separate cards increase bandwidth since it'd be using different PCIe slots versus the single Duo card?

Thanks for the help in understanding this!

 

[DrEGPU]

I really think it depends on what your use case is. If you can leverage the infinity fabric link (84GB/s; yes gigaBYTES) of the Duo, you might be better off with that. As opposed to the PCIe 3.0 slot at 32GB/s.

 

[casperes1996]

I really think it depends on what your use case is. If you can leverage the infinity fabric link (84GB/s; yes gigaBYTES) of the Duo, you might be better off with that. As opposed to the PCIe 3.0 slot at 32GB/s.

You can connect two regular cards together with an Infinity Fabric Link external to the card too. One even comes in the box.

But the duo allows you to have 4 GPUs total in the MPX modules. Inter-GPU communication will be slightly faster on the same card but system communication may be slightly slower if communicating with both GPU dies at once.

Overall I would expect a fairly negligible difference however

This is qualified guesstimations and not measured

 

[rondocap]

I did many tests on this with the Vega ii and Vega ii duo, never was able to find the 16x vs 32x bandwidth limitations - but similarly the same is true on the W6800x Duo. The single seems to have slightly better performance, so most likely two of them would be slightly faster than a Duo.

Check the other. threads for some benchmarks I did on the Duos