16 PCIe lanes

[mrbilky]

I have a 10GBe mellanox connectx 2 dual port card that is 8x will it run in a 4x wired 16x slot at a slower speed or won't work at all? My cpu is an i7 6700 and from what I see it has 16 PCIe lanes I would like to get a motherboard with more slots and I would like to have a GTX 1050 GPU, my 10GBe card and a 4 or 8 port HBA is this a pipe dream or is it doable? If the CPU has 16 lanes does the motherboard chipset have any of its own lanes or are they part of the 16

[JorgeB]

6 hours ago, mrbilky said:

I have a 10GBe mellanox connectx 2 dual port card that is 8x will it run in a 4x wired 16x slot at a slower speed or won't work at all?

Yes, I have one working on a x4 slot.

 

6 hours ago, mrbilky said:

If the CPU has 16 lanes does the motherboard chipset have any of its own lanes or are they part of the 16

Assuming it's a desktop board, the 16 CPU lanes are the ones used by the x16 graphics slot (or split two ways for both graphics slots in an SLI board), server boards usually split them in two x8 slots, all the other expansion slots use the PCH lanes.

[mrbilky]

Yep it's a desktop board so in theory I should be able to run a GPU at 8x an HBA at 8x and my 10GBe card at 4x from the chipset, if I've read correctly most of the time a GPU is only running at 8x so I would have some headroom for other purposes as I don't think I'll be pushing my GPU does an HBA need all the bandwidth of an 8x slot?

[JorgeB]

Just now, mrbilky said:

Yep it's a desktop board so in theory I should be able to run a GPU at 8x an HBA at 8x

Only if it's a board with SLI support.

 

1 minute ago, mrbilky said:

if I've read correctly most of the time a GPU is only running at 8x

No,it's always x16 on non SLI desktop boards, or always x8 on SLI boards with the second GPU slot in use.