Slot no’s are confusing but pice clarify 1gpu and 4x nvme or ssd. For sure it’s fine but only works on x series intel platform not normal one not sure for the AMd may be thread ripperSent from my iPhone using Tapatalk
Even nvme has ram and it depends on where you copy between nvme things slow over time at 45gb it’s shouldn’t. But it seems recently firmware 2401 z370 slows the overall speed. Did you copy single file as iso can be looked as single try single big 4K ...