Unless, I have misread the Samsung rated specs, or it has been mis-published and the specs are actually rated for PCIe 2.0x4.or the Asus spec for that 2nd PCIe x16 slot has been wrongly published. The throughput for PCIe 2.0 is about half that for PCIe 3.0 given the same number of lanes. That's why I am surprised you managed to achieve full spec speed via PCIe 2.0x4 when the Samsung XP941 is rated for PCIe 3.0x4. I suspect when i install a 950 PRO NVMe SSD, i'm going to have to decide if i want to keep that video card or remove it to give me access to that PCIe 3.0 slot Nice mobo but, as you discovered, the M.2 slot is PCIe 2.0x2 similar their expensive X99M-WS, which is a disappointment since an Intel LGA2011 cpu has more PCIe 3.0 lanes than a LGA1150 cpu, and Asus chose not to allocate 4 of those lanes to the M.2 slot. I couldn't access the 2nd slot as it is covered by my GTX 750 Ti video card

And Arthur_S has a MSI R9 380 GPU occupying the first slot, so he would have to install any M.2 PCIe Adapter Card in the second slot unless he is willing to forego the MSI R9 380 GPU. The second slot is PCIe 2.0 at x4 lanes, similar to Arthur_S's Gigabyte F2A88XM-D3H. NO - see above response and my system specs in my signature

you are not using a 3rd party graphics card but using the Z97 on-board graphics instead. Did you install the M.2 PCIe Adapter Card in the first or the second x16 slot of the Asus Z97M-Plus? - actually in the last slot which is PCI x4 (i assume that it's PCI 1.0 - nothing in the manual gives any indication)įrom the results you posted, I would guess the Card is installed in the first slot (usually used for a graphics card), i.e.

Plug usb 3 card into pci2 x4 or x16