You're going to run into this problem a lot because there simply aren't enough PCIe lanes to go around. A Zen 3 has PCIe Gen 4 x24 lanes and the X570 chipset has an additional PCIe Gen 4 x16 lanes. These are allocated by the motherboard manufacturer to the GPU, PCIe slots, M.2 slots, SATA ports, LAN, Wi-Fi, sometimes additional USB 3.2 Gen 2 10 Gbps or Gen 2x2 ports, etc. Furthermore, as you have found, you may or may not be able to reallocate the lanes in the BIOS, or some slots or ports get disabled when others are in use.madbrain wrote: ↑Sat Oct 23, 2021 7:37 am So, it turns out that on my current X99 motherboard, 2 of the 10 SATA ports are disabled when M2 is in use, so I really only have 8 usable SATA ports, not 10. That's documented in the manual for the MSI X99A Raider. Still 2 more SATA than on the Prime X570 Pro.
What's much more concerning is that my LSI SAS2 x8 card, in an x16 slot, is now running at just x1 according to HWINFO. The peak throughput on the striped 8 x 1TB Samsung 860 that are attached to the LSI card has dropped to "just" 900MB/s, barely 1.5x SATA-3 bandwidth. It used to be about 4GB/s. I don't know when this regression happened, sigh.
Sadly, the motherboard BIOS has no settings for PCIe slot bandwidth at all.
Maybe adding the NVMe in the M2 slot a year ago also stole lanes from one of the PCIe x16 slots. But that part is not documented in the motherboard manual. There is no way to disable the M2 slot in the BIOS. I fear physically removing the NVMe from the M2 slot is the only sure way to test that theory, but my failing vision won't allow me to do that myself anymore. Those M2 screws are just too tiny. Also, the NVMe SSD is the current boot drive, and it would be a PITA to test - involving a full OS install to a small SSD I have laying around. Or maybe cloning, but I don't think I have a big enough SATA SSD for that.
Perhaps swapping PCIe slots between the Aquantia x4 and LSI x8 cards would partially solve the problem. Aquantia card running at PCIe 3.0 x1 would not quite hit 10 Gbps anymore, though. LSI card running at PCIe 3.0 x4 would not quite hit 4GB/s either, but it should be close, at least in theory. It's certainly an easier test to switch PCIe slots than to remove the NVMe drive.
So you may have to get creative. For example, it looks like you need a lot of SATA ports rather than NVMe, so there are adapters to convert an M.2 slot to 5 SATA ports like this:
https://www.amazon.com/Internal-Non-Rai ... psc=1&th=1
Or, you could get a motherboard with 10 GbE LAN built-in which will free up a x4 slot.