Hi,
I'm using the ROG MAXIMUS VIII HERO for my motherboard.
Is anyone able to confirm the layout of the PCIe slots on the motherboard and how they are configured?
(I've asked asus support and as usual not very helpful)
From what I understand the two grey slots will use the CPU PCIe lanes and the m.2 slot (for pcie devices) will use the DMI interface?
Do the black PCIe slots also use the DMI interface or will they run through the CPUs PCIe lanes?
Thanks in advance, this has been driving me nuts!
Yep.
Both grey x16 PCI-e slots and the m.2 slot are running off the CPU, and the black PCI-e slots are running off the PCH.
I'd assume that the m.2 slot would run switch to the PCH if you're using two x16 devices, but I'm probably completely wrong.
That's kind of weird though... why would the PCH and CPU share IRQ's? Or is there some magic switcharoo taking place if you run SLI/CFX? I remember JJ from Asus mentioning something about their pcie engineering was exceptional.
Edit: Maybe the IRQ isn't dependent on a component level though, only logical. No idea.
From what I've read the M.2 will use the PCH lanes, if there is some asus voodoo switching going on then it's possible it could use the CPU lanes if you're not running SLI/CFX.
I couldn't make sense of that page from the manual.
I can understand the names for each component on the board but then the A,B,C column I have no idea what they represent. :S
It's a kind-of-legacy thing from ages long forgotten (and mostly gone), but it gives an indication of how things are routed on the motherboard.
I could just be rambling, but:
It appears INT C and D are PCH interrupt paths, and INT A and B are CPU ones.
That would mean everything in columns A and B is run by the CPU, and the other two by the PCH.
So, pretty much what Zavar said, except the last slot is governed by the CPU too:
You can read about IRQ here: http://www.realworldtech.com/irqs-explained/
So with the 1080 plugged into the first grey slot it's working at x16 electrical (confirmed through gpuz)
Putting a second 1080 into the second grey slot would run them in x8 and allow SLI.
That is all of the 16 CPU lanes used, if I add an M.2 NVMe Drive that would then run through the DMI?
No other slots could be used? For example I couldn't plug in a Thunderbolt EX 3 PCIe Card into the bottom black slot? As it runs through the CPU?
If what @ewrk is saying is true and A and B are the CPU, the graphics cards would run at x8 and x4, and the M.2 would take the other 4 lanes.
That doesn't seem right to me, though. It would make sense for the DMI to handle the M.2.
These IRQs are likely shared because the CPU only has 16 lanes while the Z170 chipset has 20 lanes. But the IRQ thing isn't really important, interrupts are not something the consumer should worry about
For the OP
The grey x16 slots will be on the CPU (it only has 16 lanes) and be 2/x8 or 1/x16, everything else will be handled by the Z170 chipset (all 20 lanes on the chipset are gen 3 btw).
Source: http://ark.intel.com/products/88195/Intel-Core-i7-6700K-Processor-8M-Cache-up-to-4_20-GHz
Is it the DMI managing that?
*depends on the CPU you use.
this is why people buy the 6850k and 5930k, more PCI-E lanes for GPUs and such
Well DMI stands for direct media interface so it's not a controller, it's an interconnect. So it would be more or less a cooperative effort (best way to describe it, I'm not 100% sure who controls who) between the CPU and chipset
All 1151 CPUs have 16 lanes
That I'm fully aware of. But x99 was a bit much for what I wanted to do and I didn't need the cores.
£300 vs £500. x99 for me would be a waste and a waste of money.
@Kiaxa Thanks for the clarification. Forgot to check Intel ARK for information on the chipset.
Two GPUs on the CPU lanes and the m.2 or other black PCI slots are the chipset/DMI ?
I'm a little confused as to what OP is worried about... If it's whether or not there's enough pci-e lanes for gaming there's not much effect as demonstrated in this article: https://www.pugetsystems.com/labs/articles/Titan-X-Performance-PCI-E-3-0-x8-vs-x16-851/
I would imagine there's enough lanes for whatever they plan on doing since there's 20 from the chipset in addition to the 16 from the cpu. I can't say for certain since I don't know what devices are to be connected to the motherboard through pci-e but for most consumers there's ample and it's usually not something worth worrying about.
Hopefully I can clarify for you @ThatBootsGuy
I currently have 1 GTX 1080 connected to the first slot.
I'm planning to purchase a second GTX 1080 along with an Samsung NVMe 960 SSD (M.2)
From what I understand so far this shouldn't be a problem.
I would also like eventually purchase a Thunderbolt EX 3 PCIe card, that would be connected to a thunderbolt storage array in another room. (I don't like HDDs, built a quiet PC and I could hear the HDDs)
NAS isn't really a solution as I'd like the speed over ease of use.
yeah there shouldn't be any problem. so far you'd be using 20 (16 of which from the cpu if my memory serves me correctly) so that leaves you with 16 for the thunderbolt card and whatever else you decide to throw in there.
Yeah you're correct. 16 from the CPU. 4 from the DMI.
I think thats everything cleared up! Thanks you were all more helpful that Asus support! :)
/thread :D
Since this thread is solved I will be closing it unless op wants it opened again
