question about Z97 chipset, m.2 pcie ssd, and pcie lanes

honey2015

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Oct 8, 2015
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let me explain, on following setup.. Broadwell 5775C, motherboard Asus Deluxe Z97 usb3.1 (nfc&wlc), I would like to learn and know how pcie lanes is distributed.

this motherboard have two pcie 16X 3.0 slots, and I think one 16X 2.0 slot. also, it have m.2 slot but it can work only with 2X 2.0 pcie lanes.

because of Samsung Pro 950 SSD, which require 4X 3.0 pcie lanes to get full speed, I had put it on pcie 16X 3.0 slot with Asus adapter. and it work at full speed.

there is still no dedicated Gpu, for now Iris 6200 is enough, but in time I will look to add some top dedicated Gpu.

so, when I put Gpu into another pcie 3.0 slot, it will automaticaly work as 8X 3.0, because SSD use 4 pcie lanes already from another slot, do I understand it good?

or do I have to make any adjustment in Bios?

tnx
 
Solution
If using the x16_3 slot, most probably the card will work at x8. No big loss in performance.
The CPU provides 16 lanes and the PCH 20 lanes, but the X_3 is connected to the CPU. Unfortunately, you can't use the X_2 due to the card's size.

RCFProd

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You know the PCIE lanes operate seperately right? Each lane has Its own specified spec. One is x16, one is x8, one is x4. Depends on the motherboard. So if your SSD requires 4x 3.0, you don't put it in the x16. Because it doesn't require x16. Leave the X16 for the GPU.
 
If using the x16_3 slot, most probably the card will work at x8. No big loss in performance.
The CPU provides 16 lanes and the PCH 20 lanes, but the X_3 is connected to the CPU. Unfortunately, you can't use the X_2 due to the card's size.
 
Solution

honey2015

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so, it will end up working as GPU 1x8 pcie lanes, and ssd 1x4 pcie lanes (total 12 used), right?

I have read that even new Titan X Pascal is just few percent slower when running at 8X pcie 3.0, instead of 16X pcie 3.0.