I heve read that before, motherboard itself disables two SATA posrt (5,6) when connect both m.2 ports. All the other onboard devices shares PCH lines (USB, Audio, Raid, SATA, etc.). Is it matters that m.2 drivers run on RAID0 and add an extra Raid support? Can I disable some extra USB hub don't need all of them will that add an extra line or bandwich?
To be honest I am a little out of my depth even though I use a Z370 motherboard but only with on NVMe drive. I know we lose a couple of SATA ports but this is a slightly different issue. I did find this thread:
'On the intel side, for example z370:
x16 pci 3.0 lanes for the gpu
4x 3.0 lanes to the chipset (its not pci, but its the same speed as 4x 3.0). There are 24(iirc) 3.0 pci lanes off of the chipset. But they must all share the x4 link. All the usb ports, sata ports, everything else must share the 4x lanes.
All m.2 drives will be connected to the chipset and share the 4x chipset lanes.
You can have 1 m.2 drive running at near full speed(still has to share with sata ports usb ports, etc). Or if you have more then 1 m.2 slot they will have to share. If you have 2 top end m.2 drives they would be running at about half their maxium read speed. 3 top end m.2s would be down to 1/3rd their max speed. You could access any 1 drive at near full speed, but if you tried to do more then 1 at the same time they would all suffer.'
There are some great people on here who should know the exact breakdown on the PCIe lane sharing side and fingers crossed they will jump in.