Not just SLI, but also non-SLI multi-GPU clusters which are common in machine learning, e.g.: http://timdettmers.com/2014/11/09/model-parallelism-deep-learning/

Not just SLI, but also non-SLI multi-GPU clusters which are common in machine learning, e.g.: http://timdettmers.com/2014/11/09/model-parallelism-deep-learning/ http://timdettmers.com/2014/11/09/model-parallelism-deep-lea... And even if you don't use GPUs, now there are M.2 SSDs which commonly use 4X PCIe lanes, see https://en.wikipedia.org/wiki/M.2 https://en.wikipedia.org/wiki/M.2