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Lanes confusion. 6600k, Z170

post #1 of 8
Thread Starter 

I am trying to sort out the details of LANES in Z170, Asus style. I have a ROG Maximus VIII Gene.

 

I THINK I can use;

 

1. MSI GTX 980 Limited Edition in 16x lanes 3.0 PCIe mode,

2. Intel 750 NVME SSD in 4x lanes in the 4x slot mode,

 
... all at the same time.
 
I am currently using the first two just fine. I haven't bought the 950 yet and I am just checking my thinking.
 
I don't plan to use any SATA ports so that keep the total to 24 lanes.....I think.
 
TIA
post #2 of 8
Your processor only has 16 lanes. Your GPU would be at x8 and both your SSDs at x4.
post #3 of 8
I dont think thats correct... Pretty sure the gpu will run on 16x because the first slot only shares those 16 lanes with the secound slot. The 4x slot and the m.2 slot are connected to the z170 rather than the cpu itself. I cant tell from your manual but im fairly certain you can run all three at full speed...

Edit- your z170 has an additional 20pcie lanes for usb/storage/lan. So your gpu will be 16x direct to cpu. The m.2 and the intel 750 will both run at 4x as long as they are configured to in your bios but they are not connected directly to the cpu, instead they will go through the z170 and up to the cpu over DMI 3.0... Im not sure what the limitations of DMI 3.0 are but i cant imagine it making a huge difference

Give this a quick read... http://m.hardocp.com/article/2015/08/12/intel_z170_chipset_summary/#.V2hWx_T3anM
Edited by infinite0180 - 6/20/16 at 2:07pm
post #4 of 8
Thread Starter 

Thanks so much for the quick responses. I think a lot of us have confusion about how Skylake lane allocation works.

 

I probably wasn't clear...infinit0180 is correct...I am currently running the GPU and the Intel NVME at full lanes...totaling 20 lanes. I am just not sure what the M.2 NVME mode Samsung will run at.

 

For that matter I think that there even more lanes running for USB, SATA, etc. support but all of Intel's literature, that I can find, gets very vague when it comes to defining how many lanes can run at once and what each set of lanes supports......all in one place.

post #5 of 8
Techniquely speaking skylake has 36 lanes, but only 16 are direct to the cpu for graphics... The other 20 are divided up however the mobo designers wants and connected to the z170. The z170 is connected to the cpu via DMI3.0... So, these 20 lanes Include usb3.0, sata, m.2, ect... The only downside is that those 20 lanes are not direct to the cpu, like i said, the z170 converts them and sends them over DMI3.0 to the cpu. Soo even though those devises are connected over pcie 3.0 lanes, they are ultimetely limited by the transfer rate of DMI3.0... Check out the picture on that link and you will see what i mean... That is why RAID on 2 m.2 will hit a wall, because DMI3.0 doesnt have the bandwidth
Edited by infinite0180 - 6/20/16 at 2:39pm
post #6 of 8
Thread Starter 

Once again, you have the best info I have seen all together. And I should have pieced it together better but I STILL feel like even with this added piece to the puzzle, it is really hard to understand what gets squeezed when you beef up one of these DMI lane groups. Also I get the impression that some of the motherboards have EXTRA controllers, including PLX types that somehow bring in more lane switching alternatives.

 

Boy, would I love to see a group Guide on this subject. I think it would be worth the effort because so many of us bought into Skylake just because of the lane restriction on our Z97 rigs.

post #7 of 8
Ya man i guess it really does depend on the mobo manufacturer... But in order for my mind to simplify it and understand it i just try to keep it cut and dry ya no. I just bought a z170 board and im excited to start my build
post #8 of 8
I came here looking for the answer to this question. I have an asus sabertooth z170, im running a 950 in the m.2 slot, samsung 750 ssd and a 7500 rpm drive over sata, and have a intel 750 to add to the mix.
It is a bit confusing but I think you'll be fine, i.e everything runs at full speed. Regarding the DMI performance, I think it's very close to the point of no noticeable performance hits.
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