

What Is NVLink? And How Will It Make the World’s Fastest Computers Possible? - eslaught
http://blogs.nvidia.com/blog/2014/11/14/what-is-nvlink/

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sprayk
As far as I can tell, this is a replacement for PCIe for connecting a GPU to a
computer. Does this mean there will be a new connector for connecting a GPU,
or are GPUs expected to be soldered to the board?

Is NVLink attached to the northbridge, or is it a replacement for the
northbridge? Is the northbridge even a thing in computer architectures this
large?

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valarauca1
I think NVlink is a re-configuration of the PCIe standard, while using the
same physical pathways it communicates in a different way.

Currently PCIe can talk directly to the memory controller, and have direct RAM
access without CPU overhead. So the whole GPU's run as fast as CPU's can give
them memory is a bit false (but since memory controllers are on chip now I
guess its true?).

What this maybe, if I had to guess. Is dynamic lane allocation. Where 1 GPU
can free its PCIe lanes to let other devices use them. So 1 GPU can use all
~90 or how ever PCIe lanes IBM power9 chips have, instead of 4 GPU's each
having 22.

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sparky
The only real similarity to PCIe is that they're both high-speed differential
signaling standards. This article has a good overview of what is known:
[http://www.anandtech.com/show/7900/nvidia-updates-gpu-
roadma...](http://www.anandtech.com/show/7900/nvidia-updates-gpu-roadmap-
unveils-pascal-architecture-for-2016) .

For an example of what the signaling might look like, see
[https://research.nvidia.com/publication/054-pjb-20-gbs-
groun...](https://research.nvidia.com/publication/054-pjb-20-gbs-ground-
referenced-single-ended-short-reach-serial-link-28-nm-cmos)

