CPU vs. PCH lanes with GPU(s) and M2 drives

[jsgrant31]

Hi all,

This post could go in several sub-forums; I hope I've chosen correctly. I want to upgrade later this year with Kaby Lake i7, DDR4, new mobo, and M2 SSDs (with plans for Pascal/Volta GPU and 4K OLED later). The only thing I'm confused on right now is the CPU/PCH lanes and whether or not what I want to do is too much for the system. From what I've read the CPU should have 16 lanes and the motherboard PCH has 8. Normally a GPU uses 16 CPU lanes (but can use 8 with same performance) and other peripherals use the PCH lanes.

I want a 950 Pro M2 as the boot drive, a second 950 Pro M2 for important games, and one or two SATA SSDs/HDDs (or maybe even another M2) for other storage. I've always kept to one GPU (I do have a second for PhysX currently), but I am curious if I could SLI GPUs with the M2 drives. I don't use sound/wifi cards or any other peripherals that would use up these lanes.

The problem is I don't really understand how many lanes each peripheral takes up and under what circumstances. A GPU uses 16, but it can apparently use 8 in certain situations (SLI or other). An M2 drive seems to use four, so if I wanted two that would make eight and any other SSDs/HDDs would also use up some lanes(?). I want to be able to count this for myself but I'm having trouble. Would this motherboard get me what I want?

Thanks for your help. I've been reading about this (I know there are a lot of threads), but lanes are a confusing concept for me. My system specs are in my signature for reference.

Cheers

 

[ak47jar3d]

Yep, that motherboard supports 36 total lanes (20 from pch and 16 from processor) so you use sli and multi m.2 ssd in secession.

 

[Sneaky_Castro]

Finally a definitive answer to this question, I too have been planning on using multiple gpu's and m.2's as well as a wifi card hopefully. I would like to know how it all works out for you jsgrant31, I've heard from many people that skylake builds have a max of 20 lanes, but after reading more into it I found exactly what you said. The CPU has 16 lanes and the mobo (PCH) has 20 lanes, now I know that sli/crossfire setups can use a max of 20 lanes (x8/x8/x4) but I do believe that the 20 PCH lanes are specifically for extra peripherals like the M.2's sound/wifi cards and the like. So maybe it's possible that the bottom pcie slot is either a x4 or routed directly to the PCH and thats the most a gpu can utilize from the PCH. IDK just speculating. Thankyou!