It indicates it has 3 x16 slots, but one covers up an m2. That will probably be OK (3 GPU's on 1 m2 connected FPGA accelerator), but I def am not an authority. That represents my best target on first pass.
Hopefully this helps, spurns some discussion and research.
The x16 (or 16 lanes) number refers to the bandwidth and size, that said, just because it is a x16 size slot does not mean it will run full bandwidth. The processor has a certain number of PCIE lanes that it will support, as does the chipset. Most modern consumer intel cpus will support 16 lanes, with the chipset supporting another 16+ lanes. For example the z270 chipset supports 24, so any system with that will support 40 lanes total. This is why you see these mining motherboards with an insane amount of 1x sized pci slots to use with risers. Normally mining doesnt require much pcie bandwidth as everything is computed on the GPUs. But when you have instances where the gpu needs to communicate with something else (i.e. an accelerator) then bandwidth becomes an issue
short version is this (pls correct me if im wrong):
acorn needs 4 pcie lanes at gen 3 speed. this can be via an acorn in a m2 slot or in a pcie-m2 adapter provided the pcie slot that adapter is in is configured for 4 pcie lanes at gen 3 speed. this allows up to 4 gpus, each connected with one pcie lane at gen 3 speed to be accelerated. ie cards on x1 risers for example.
not all 16x slots have 16 pcie lanes, the bios can change that to a point.
my onda board (8 full size x16 slots, most that run with one pcie lane) for example has no m2 slots, but slot 0 can be run with 4 pcie lanes at gen 3 speed. so i put a pcie->m2 adapter with the acorn in that, and 4 cards get the benefit. the three other cards run on their own with no help from the acorn.
btw AFAIK cpu power has not been mentioned yet. G4400 here but easy to upgrade. memory was mentioned also but no minimum, just more is better.
not sure if this is what you were asking, if not my apologies
I agree with everything you said but with one thing. My understanding from GPUH was that each of the attached GPUs only required one pcie lane at gen 2.0 speeds, not 3.0. I could be wrong here as well, that is what I understood from the discord channel.
And as for CPU, on the discord channel, I asked about how old our CPUs can be, and i7 gen 2 are fine, heck even old Pentium e5200 are fine, so other than running your OS, the CPU does not play a role
