X99 PCIe lane switching

makopack

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Ok, still a little confused...

I'm planning to pick up the X99A SLI Krait Edition MB in the next 2 weeks. I also plan to run 2 video cards, the M.2 port as a PCI-E 4X device and the CPU will be a 40 lane one.

From what I found in the MB manual, I should be able to do the following:

Slot 1 - 16x 3.0
Slot 3 - 16x 3.0
M2 - 4x 3.0

That accounts for 36 of the lanes. Shouldn't I be able to plug in up to 4X worth of lanes into the lower 2 16x slots (#5 and #6)?? Because the manual just shows "-----" in those blocks. I assume it's ok to plug something else like a Soundblaster card (yes I know there's built in audio... I have a reason for a 2nd sound card) etc. so long as they don't use more than 4x right?

Or will doing anything in those 2 slots cause Slots 1+3 to drop down to 8x mode???
 

KedarWolf

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If I want my video cards in the top two slots and put a pci-e Intel 750 which runs at 4X in the fourth slot will the video cards 16/16? I have a 40 lane CPU.
 

badboy2k

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KedarWolf said:
If I want my video cards in the top two slots and put a pci-e Intel 750 which runs at 4X in the fourth slot will the video cards 16/16? I have a 40 lane CPU.
what board? you have said you have a 40 lane CPU but not what board you have!
 

strike@karkand.net

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So I've almost exclusively bought MSI products in the past, because I've never had issues and this was enough to make me stick to them... until now.

I've recently bought an entirely new system:
- Intel Core i7 6900K
- Kingston HyperX Predator DIMM Kit 16GB (x2)
- MSI X99A Gaming Pro Carbon
- MSI GeForce GTX 1080 Gaming X (x2)
- And a whole bunch of Noctua PWM fans

(Please don't assume that I'm rich or anything. I'm a student. This was a major investment for me. I've used money I saved over the course of about three years!)

Right from the start I've faced issues with the ASMEDIA USB 3 controller (*this*), but since I don't really need that many USB connections anyway, I've decided not to use them and just wait this issue to get fixed per driver update or something.

But there's another problem, that I think is way more severe. The top GTX 1080 of my SLI setup is absolutely suffocating, because MSI thought it would be a great idea to have no free space between dual slot graphic cards on the X99A Gaming Pro Carbon. Sorry for needlessly bashing the engineers of MSI, but I'm just so infuriated about this! Obviously I blame myself for this, too, I should have definitely paid more attention to this before I purchased the motherboard. Well, basically one GTX 1080 is always running up to 20?C hotter than the other one, even with all fans manually set to 100%.

Would SLI still work if I used PCI_E1 and PCI_E5 (with a sound card in PCI_E3 and an SSD in the M.2 slot)? I guess they wouldn't be running in x16 mode then? To be perfectly honest, I'm even too dumb to make sense of the graphs in this thread. And I cannot test this, because I have no SLI bridge that long and before spending about ~$20 on a SLI bridge or even $50+ on a SLI-HB bridge I thought I'd ask you guys.

Thanks in advance!
 

Nichrome

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Hi

SLI should work just fine with PCIE1 and PCIE5 slots being used. Of course, it will not be at x16 speed, but the difference is so small that you wouldn't notice a difference.
Also it is normal that top card runs hotter than the other. But if top card's temp doesn't exceed 85C under full load then I wouldn't worry about it.
 

flobelix

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Yes, E1 and E5 will work in SLI (at x8/x8). It is the best idea with this setup. You won't notice any difference compared to x16/x16 anyway. Lower temperatures and full boost clockrates are more important.
 

strike@karkand.net

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Nichrome date=1467969661 said:
Hi

SLI should work just fine with PCIE1 and PCIE5 slots being used. Of course, it will not be at x16 speed, but the difference is so small that you wouldn't notice a difference.
Also it is normal that top card runs hotter than the other. But if top card's temp doesn't exceed 85C under full load then I wouldn't worry about it.
So, you're admitting this is worrisome? :undecided:

After 3 minutes the top card runs 93?C while the bottom card still is about 20?C cooler:


After 15 minutes the top card is running at a mere 949MHz thanks to thermal throttling:


The ambient temperature is 20?C (AC controlled). I still don't understand why MSI chose to design the PCIe slots on the X99A Gaming Carbon like this, when most graphics cards these days are dual slotted. I'm really upset about this... :(
 

Nichrome

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Yes 93C is quite bad, and better to move cards around to get them at x8/x8 but with lower temps.
 

flobelix

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The layout decision is bad and was much criticized. However it is that way on all MSI X99 boards below Gaming 9/Xpower series except for the X99A Raider. You can still use an SLI setup without any problem populating E1 and E5 like suggested. x8/x8 will not hit the performance in a noticeable way.
 

strike@karkand.net

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Nichrome date=1468049534 said:
Yes 93C is quite bad, and better to move cards around to get them at x8/x8 but with lower temps.
flobelix date=1468065934 said:
The layout decision is bad and was much criticized. However it is that way on all MSI X99 boards below Gaming 9/Xpower series except for the X99A Raider. You can still use an SLI setup without any problem populating E1 and E5 like suggested. x8/x8 will not hit the performance in a noticeable way.
Thanks for the help and honesty guys! I switched slots and now there's a difference of about 5?C instead of 20?C. So I'm happy with that. Although I wonder what the performance difference between x16/x16 and x8/x8 looks like. Someone who buys a system like this probably wants all the performance they can get. :-P)
 

naveeed

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Dear all,
I have a pc with following specification.


X99A GAMING PRO CARBON
Bios : 1.2.
INTEL 6800K
CORSAIR H100I COOLER

SAMSUNG SSD 512GB
32GB CORSAIR RAM
1200W PSU
ASUS GTX 980TI X 2
WINDOWS 10 / 106
Nvidia Drivers. Ver. 368.81

TWO MAJOR ISSUE FACING.
1. BOTH GPUs working at x8 Speed.
(Installed 6900K CPU,Which is 40 Lanes,Tested with

two X99A GAMING PRO CARBON Motherboards,
Still the same issue,
2. In Nvidia Control Panel. The first GPU on PCIE1

shows as second GPU & on E5 shows as Primary (No.1)

GPU.
As I feel The GPU#1 on PCIE1 should show #1.

Earliest help is anticipated,
 

badboy2k

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naveeed date=1470866069 said:
Dear all, I have a pc with following specification. X99A GAMING PRO CARBON Bios : 1.2. INTEL 6800K CORSAIR H100I COOLER SAMSUNG SSD 512GB 32GB CORSAIR RAM 1200W PSU ASUS GTX 980TI X 2 WINDOWS 10 / 106 Nvidia Drivers. Ver. 368.81 TWO MAJOR ISSUE FACING. 1. BOTH GPUs working at x8 Speed. (Installed 6900K CPU,Which is 40 Lanes,Tested with two X99A GAMING PRO CARBON Motherboards, Still the same issue, 2. In Nvidia Control Panel. The first GPU on PCIE1 shows as second GPU & on E5 shows as Primary (No.1) GPU. As I feel The GPU#1 on PCIE1 should show #1. Earliest help is anticipated,
that board is electrically wired the same as the X99S SLI Plus so 1 and 5 are on shared lanes off slot 1's x16 lanes so its splitting them x8 - x8!

 

naveeed

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badboy2k date=1470887293 said:
that board is electrically wired the same as the X99S SLI Plus so 1 and 5 are on shared lanes off slot 1's x16 lanes so its splitting them x8 - x8!

Thanks for your quick reply.

If I connect DP/HDMI Cable to GPU #1, it take as above image.
If I connect DP/HDMI Cable to GPU #2, it take as Primary GPU.
Any clues why the GPU #2 taking as Primary.

Regards
 

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badboy2k

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i think that is a NVIDIA thing to offload the bulk of the display outs to the lower card to keep temps more even when they are used in SLI as the lower card will be cooler then the top one so moving the driving of displays to the lower reduces the heat of the upper card as its just a compute engine only and the cooler card has more headroom for the extra heat a display out generates as its extra processing for the signal!

i do not think that can be changed to flip them back around! (most boards for years from MSI have been like that where the lower is set as primary)
 

jidri.luks

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badboy2k date=1470887293 said:
that board is electrically wired the same as the X99S SLI Plus so 1 and 5 are on shared lanes off slot 1's x16 lanes so its splitting them x8 - x8!


I got the issue with my PC like that. I have
i7 5820k
2x MSI R9 390 G8 Gaming
MSI X99A Gaming 7
I use pci-e1 and pci-e 5 and Bios says vga in slot 1 is running at x4 and in slot 5 is running at x8. If I use only one card in first slot, speed is x8, in slot 2 is it x8, not x16 and both cards as I wrote x4/x8  pci-e1/pci-e5. I dont have m.2 ssd and no sound or other pci card. I took both cards to my friend, he has 5820k and same MB. we didnt try CF but both cards single in pci-e1 run at x16, Is my motherboard damaged? And more.....Board Explorer in Bios says, I got all 8 RAM slots empty. I got there 6x8 GB Kingston 2666 mhz ddr4, and today, I was forced to clear CMOS, i did it 20 times and PC still didnt turn on, after 2 hours of trying I find issue, 2 dead ram modules.... Can someone help me figuree it out? Or its tottaly lost, and i would like to claim a warranty. (sorry for my English). I hope everyone understand.
 

Svet

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@jidri.luks
if you are looking for troubleshooting, please open new own topic and also provide details system specs,
see >>Posting Guide<<
 

rgiarusso

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Planning out a build and trying to figure out how to go about configuring everything properly (if I need custom BIOS).

Intel i7-6850K (40 PCIe Lane)/MSI X99A Gaming Pro Carbon
2 MSI GTX 1070s, 10Gb Networking Card, MSI GT 710, and Samsung 950 Pro M.2 SSD.

Trying to get the following config:
PCI_E1: x8 - GTX 1070
PCI_E3: x16 - GTX 1070
PCI_E5: x8 - 10Gb Networking
PCI_E6: x4 - GT 710
M.2_1: x4 - SSD

Is this even possible?
 
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