Comment by namibj

It's sad that NDA fetishist Broadcom has a de-facto monopoly on PCIe fabric switches; notably we would have functional open source drivers for at least simpler topologies for a while now, and could just set up cheap FNN topologies by using (usually NMVe targeted) bifurcation support on hosts to get several x4 ports with only a comparatively cheap retimer out into "mini SAS hd" (the square shaped 4-Lane connectors) or QSFP+ ports; and then have a few meters reach on generic DAC cables from such standards (even Skylake-era SAS ones (nominally 12 GT/s; PCIe4.0 is 16 GT/s) should typically manage PCIe4; that's just under 64 Gbit/s from each link, with typical desktop/gaming systems delivering 3~5 links without complaints next to a dGPU (that one at fewer than full lanes).