Motherboards such as the Aorus Master/Extreme have 3 NVME slots, but 1* runs through the chipset rather than through the CPU. It seems to me like that could cause a slowdown in throughput.
I would rather run all three NVME drives directly to the CPU, even if that means running the GPU at x8. This makes more sense to me with a PCIE gen 4 GPU like the RX 5700 series, since most of the x16 bandwidth is just going to be wasted.
I know their are add-in cards like the 4 drive, x16 add-in card from gigabyte, but I wouldn’t want all 4 drives. At most, I would want 2 drives (taking up only 8 lanes. Also, I don’t know how well those add-in cards work with software level RAID like RAID-Z with ZFS. Does the Gigabyte card present as a single storage device (with hardware RAID across the drives) or does it simply make each drive available to the CPU.
Are there just 2-drive x8 add-in cards that support PCIE gen 4? Or is the bandwidth of running the drive through the chipset enough that I can use all three existing m.2 slots without a meaningful degradation in performance?
*Actually, from the specs it looks like 2 run through the chipset and only one directly connected to the CPU. I’ve heard that only one connects through the chipset, but it makes more sense to run two through the chipset if you want to keep the GPU running at x16 configuration.