Adding 4 port PCI-E card to ASUS Z97-a's 3rd PCI-e lane?

[cammada]

I have ASUS Z97-A motherboard and it has 2x PCIe 3.0/2.0 x16 slots and 1x PCIe 2.0 x16 slot. I want to know if the 3rd PCIe slot does or doesn't shared the bandwidth with other 2 PCIe 3.0 slots?

What I am trying to achieve is to add more sata HDD but I have used up all 6 sata ports so I was thinking of buying 4 ports PCIe Sata JBOD controller card and slotted it into 3rd PCIe 2.0 x16 slot but my concerns is that it will affect my AMD R9 270X video card performance if its bandwidth does shared with the first two PCIe 3.0 slots.

I currently have m.2 drive install and I don't want to use PCIe 2.0 x1 slots because it share the bandwidth with m.2 slots.

if anyone has better solution to share with, please do. Thanks in advance.

 

[WyomingKnott]

Judging from the specifications page here: http://www.asus.com/us/Motherboards/Z97A/specifications/ , the PCIe 2.0 x16 slot is physically x16 but only has two lanes, if I'm reading what's on that page correctly. These lanes are not shared with anything else. Bear in mind that your total throughput for all the drives on that card will be limited by the two PCIe 2.0 lanes.

2 x PCIe 3.0/2.0 x16 (x16 or dual x8)
1 x PCIe 2.0 x16 (x2 mode)
2 x PCIe 2.0 x1 *1
2 x PCI
*1 : The PCIe x1_1/2 slots share bandwidth with M.2 Socket 3. The M.2 Socket 3 is default disabled.