• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Looking for a Z170 board with enough PCI-E lanes

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

torin3

Member
Joined
Dec 25, 2004
I've got a Gigabyte Z170X-UD5-CF board, with a i7 6700K Skylake. Works reasonably well, but my issue is I tend to run a lot of video cards.

I haven't been able to get it to run more than 2.

I'm looking for suggestions for a board that can run at least 3 Nvidia 10 series cards.

It is ok if it is a bit spendy, as I'm limited to 1 system at home to run my cards for folding, but it has to run 3 cards.

M.2 for SSD would be nice, but not required, and I'm keeping the CPU.
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
Most available motherboards have almost the same amount of lanes dedicated to each PCIe slot and you can't really use more. When you run 2 cards then both are almost always x8. 3rd slot is x4 or x1. When you use M.2 PCIe slot then it locks last PCIe slot or lowers its speed. Some motherboards will let you run 3 graphics cards as 8+8+4 or 8+4+4 but I'm not sure which. I don't remember if any reasonable priced Z170 board had additional PLX chip or something like that. Soon will be Z270 and Kaby Lake will support more PCIe lanes.
 

FTC

Member
Joined
Mar 3, 2002
Location
Barcelona, Spain
Hi, also remeber that kaby lake is coming with a few more pcie lanes (24 vs 20 in skylake direct to the cpu plus 20+ lanes going through pch) so theoretically a Z270 board could have some more flexibility than a z170 one... few weeks ago MSI was showing a board with 3 'long' x16 pci expansion slots (although it was electrically really a 16+8+8 solution).
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
In theory yes but I'm not so sure looking at first ASUS boards specification where nothing really has changed except additional lanes for other devices like M.2 drives. I guess we have to wait some more to find out if anyone design something like 8+8+8. With M.2 and other devices like WiFi card which is getting more popular they won't add support for 3rd graphics card.
 
Last edited:
OP
torin3

torin3

Member
Joined
Dec 25, 2004
Most available motherboards have almost the same amount of lanes dedicated to each PCIe slot and you can't really use more. When you run 2 cards then both are almost always x8. 3rd slot is x4 or x1. When you use M.2 PCIe slot then it locks last PCIe slot or lowers its speed. Some motherboards will let you run 3 graphics cards as 8+8+4 or 8+4+4 but I'm not sure which. I don't remember if any reasonable priced Z170 board had additional PLX chip or something like that. Soon will be Z270 and Kaby Lake will support more PCIe lanes.

I'd actually probably be fine with an 8+4+4 solution, but it was a real shock when I couldn't get the 3rd card to work, event without an M.2 SSD in the system.

In theory yes but I'm not so sure looking at first ASUS boards specification where nothing really has changed except additional lanes for other devices like M.2 drives. I guess we have to wait some more to find out if anyone design something like 8+8+8. With M.2 and other devices like WiFi card which is getting more popular they won't add support for 3rd graphics card.

I guess I need to start looking for things like Tri-SLI listed as supported for the motherboard. Or have they dropped Tri & Quad SLI support for the newer video cards?

I'll keep an eye out for Kaby Lake boards when they hit the market. If I hadn't bought such a nice CPU, I'd probably be looking to going to an older chipset that will run more cards.

Edit: I see on Newegg some ASRock and ASUS and MSI boards that list 4x PCI-E slots that actually list modes like 8+4+8 and 8+4+4+4. In the $200-$400 range. Is there an easy way to find out of they will actually run that number of video cards other than asking questions on Newegg and hoping that someone answers? The reason I'm asking for extra verification is that my UD5 says the 3rd PCI-E 16x size slot gets turned off if you are using the M.2 slots, but I don't have an M.2 drive and it still won't run 3 cards. I actually currently have one of my 2 cards in that slot (for separation) and it is running fine, so the slot isn't disabled.
 
Last edited:

EarthDog

Gulper Nozzle Co-Owner
Joined
Dec 15, 2008
Location
Buckeyes!
X99 boards with higher end chip (more PCIe lanes) and/or a board with PLX chip is what you may need.
 
OP
torin3

torin3

Member
Joined
Dec 25, 2004

Thank you ATM! That is pretty much exactly was I'm looking for. A little spendy, but in my budget range. And 8+8+8+8 would actually let me run 4 cards on there (assuming that is possible on stock cooling on an open benching station). I might have to use 16x riser cables.

That will keep me in the running on our folding team.

Thank you again!
 

ATMINSIDE

Sim Racing Aficionado Co-Owner
Joined
Jun 28, 2012
OP
torin3

torin3

Member
Joined
Dec 25, 2004
Selwen, I already have the board. I've had mixed experiences with ASRock boards when coin mining, so I'm hesitant to push their limits.

Also, folding seems to need better than 4x when using the higher end folding cards, as there aren't enough lanes for all the traffic available. It doesn't cause any problems, other that slower production.

The board I got is supposed to allow 8x/8x/8x/8x speeds. That should let me get full production out of 4 Nvidia 10 series cards. Though I expect to use 16x riser cables to take care of overheating issues.
 

wingman99

Member
Joined
Dec 10, 2003
Also, folding seems to need better than 4x when using the higher end folding cards, as there aren't enough lanes for all the traffic available. It doesn't cause any problems, other that slower production.
How much slower is 4x in production that you have seen?
 
OP
torin3

torin3

Member
Joined
Dec 25, 2004
How much slower is 4x in production that you have seen?

I'm going off of what other people have told me, as I haven't had to operate any cards below 8x speeds so far.

But my understanding is that it is only an issue with really fast cards. If the card produces less that 200K ppd, you probably won't be seeing a hit at all. And while I'm not sure of my memory for the numbers, I think they were talking about 8-10% slower speeds.

Edit: Googling around a bit, I see this: https://linustechtips.com/main/topic/640933-folding-on-different-pcie-slots/ Last post in that thread claims 1x on a 750ti gives 60K ppd, and 16x on the same card gives 100K ppd.

Edit2: And apparently my memory is playing tricks on me. http://www.overclockers.com/forums/showthread.php/765228-Riser-question?highlight=slower I had 300K cards doing as slow as 200K on a 1x riser cable.
 
Last edited:
OP
torin3

torin3

Member
Joined
Dec 25, 2004
And....It won't boot.

The motherboard LED Q-code is only ever on 00 which the manual says isn't used.

I was getting about 1 out of 10 times the 00 would stay on and the CPU fan would run high speed. The other 9 times, the 00 would flash, the fan would pick up speed and then slow back down until the next 00 flash.

Since I only had 1 8pin ATX power cable on that PSU, I switched to a newer Corsair 1KW PSU that had 2 8pin ATX power cables. Then it would come on with 00 on and solid, not flashing, 100% of the time, but still no video.

There are also no beeps from the Motherboard.

The monitor plugged in looks like it is getting a signal for a second which triggers the power on screen, then it says no signal and goes black for about 20 seconds and the process repeats.

I don't think it is getting past POST at all.

Any suggestions? I've got CPU, RAM and SSD and DVD drive. I've unplugged the DVD with no change. I've swapped the M.2 SSD from one port to the other with no change.