Need clearing up some confusion regarding HW

[TerminallyBlueish]

Hello,
my old PC recently broke down, so I am building a new system. It will be used almost exclusively for F@H for at least couple of months, after which I'll continue folding, but maybe at a slower rate. The issue I'm facing is which Motherboard to buy. I have seen mixed reports on GPUs not working or being extremely bottlenecked by x4 and x8 PCI-E slots, some people say it's an issue, some people say it's not. What's the actual answer?

The system will be Ryzen based, so I am basically having to choose between B350 chipsets, which seem to only have one x16 and one x8 port, and X370, which seem to have two full featured GPU PCI-E ports, if I understand right.

Right now, these are the two models that I'm looking at, might change depending on what info I get about other motherboards:
MSI B350 TOMAHAWK ARCTIC
MSI X370 GAMING PRO

I would appreciate any input on the subject. The machine will be running either Manjaro or Arch Linux. The GPUs are R9 290 for primary and RX 560 for secondary, folding-only slot. Thank you.

[rwh202]

I don't know for sure, but I believe that the pci-e bottleneck only really affects nvidia on windows, not Linux nor AMD.
As for AMD, I've not seen reports either way, but given their reduced CPU demands I'd hazard that they aren't as affected

[3D_Now!!]

I wrote a post about this topic a while back, might answer your question. Almost the same GPU too.

Link

tl;dr - folding works fine on low bandwidth PCIe, especially AMD due to lower CPU>GPU communication.

[TerminallyBlueish]

I wrote a post about this topic a while back, might answer your question. Almost the same GPU too.

Link

tl;dr - folding works fine on low bandwidth PCIe, especially AMD due to lower CPU>GPU communication.

So basically, the 2.0 x16 PCI-E slot is way more than enough for the RX 560, I assume, right? I just really want to double-check before I pull the plug, cause I'm hoping this motherboard is gonna last me at least 5-6 years.

[3D_Now!!]

Yes at the time I was using the 280X it worked fine on a 2x PCI express 2.0, so a 16x PCI express 2.0 should be even better. I have not folded with AMD for over a year, but i don't think the code or implementation has changed in that time.

[jrweiss]

IMO, for a few more $$, the X370 chipset is worth it if you plan on multiple GPUs from the start.

As I understand it, the main GPU sockets will use the PCIe 3.0 lanes directly from the CPU, while the chipset will supply the PCIe lanes to the M.2 drives and other PCIe slots. Also, as far as F@H is concerned, x8 is plenty of bandwidth for any but the grandest of GPUs...