PCIe lanes / affect on video card performance

[ZenMonkey]

I have an i5-4690k, which only supports 16 PCIe lanes for some reason. Currently, my GTX 1080 uses all 16 lanes. If I install another device, like an NVMe drive or second video card dedicated to mining, how much will that affect my 1080 performance?

[VVoltor]

It won't.

[Lurick]

It will not impact performance.

x8 PCIe 3.0 lanes is still plenty

You're talking margin of error level differences.

[Dujith]

To clarify:

Your CPU has 16 dedicated lines for the GPU

It also has a DMI3.0 connection to the chipset that will provide 12 or more lanes for NVME, USB ect.

[manikyath]

Just now, Dujith said:

To clarify:

Your CPU has 16 dedicated lines for the GPU

It also has a DMI3.0 connection to the chipset that will provide 12 or more lanes for NVME, USB ect.*

*if plugged into the right pcie slot on the motherboard, consult your motherboard manual for more information.

--

on topic, as long as you have enough bandwidth (which is extremely unlikely you dont with 8 lanes, if not for some intensely bad coding on the game side of things) there's no notable difference.

[ZenMonkey]

1 minute ago, Dujith said:

To clarify:

Your CPU has 16 dedicated lines for the GPU

It also has a DMI3.0 connection to the chipset that will provide 12 or more lanes for NVME, USB ect.

 

Really? Interesting. I checked Intel's ARK listing and it just mentioned the 16 lanes so I thought I was screwed. That's good to know, but a second GPU, even if it only uses one or two lanes because it's dedicated to mining, would use those dedicated lanes, right?

[Dujith]

3 minutes ago, ZenMonkey said:

 

Really? Interesting. I checked Intel's ARK listing and it just mentioned the 16 lanes so I thought I was screwed. That's good to know, but a second GPU, even if it only uses one or two lanes because it's dedicated to mining, would use those dedicated lanes, right?

Depends on your motherboard layout. Some slots will be from the 16 Lanes for the GPU, effectively turning each 16x slot into 8x

Some slots come from the chipset and will be limited by the DMI2.0 which is PCIE 4x

 

Like @manikyath said, see your manual  

Edited August 15, 2017 by Dujith
DMI2.0 said DMI3.0 by mistake

[manikyath]

Just now, Dujith said:

Depends on your motherboard layout. Some slots will be from the 16 Lanes for the GPU, effectively turning each 16x slot into 8x

Some slots come from the chipset and will be limited by the DMI3.0 which is PCIE 4x

 

Like @manikyath said, see your manual  

totally on accident i got a mobo for my server that has a 4x slot just for this kind of purpose, or in my case, a chinese raid card

[Tiwaz]

2 minutes ago, ZenMonkey said:

 

Really? Interesting. I checked Intel's ARK listing and it just mentioned the 16 lanes so I thought I was screwed. That's good to know, but a second GPU, even if it only uses one or two lanes because it's dedicated to mining, would use those dedicated lanes, right?

mining doesnt really care about lanes, many miners use cheap cpus and mobos and hook up gpus even to 1x slots with extension cables. For video production or gaming you should try to stick with at least PCIE 2.0 16x or 3.0 8x

note that SLI requires each card to run at least at 16x

[manikyath]

Just now, Tiwaz said:

 

note that SLI requires each card to run at least at 16x

8x, not 16x.

 

and on the crossfire side of things, thats 4x.

[NumLock21]

To make it simple, your cpu Intel Core i5 4690K runs on either Z87 or Z97 motherboard.

• Both of them have options for SLI and non SLI
• SLI boards, the 16 lanes from the cpu is split into x8/x8 between the 2 PCIe x16 slots
• non SLI boards, all 16 lanes from your cpu, is used up by the 1st PCIe x16 slot.
• In a SLI board, your video card will run at x8, while your Nvme drive, plugged into the 2nd PCIe x16 slot will run at x4, leaving the 4 remaining lanes not accessible.
• In a non SLI board, video card uses all 16 lanes from your CPU. Your NVMe drive will use 2 lanes from the motherboard chipset.
• CPU lanes are Gen 3, and Chipset lanes are Gen 2. Only Z170 for Skylake and newer, have chipset lanes running at gen 3.

TLDR

SLI m/b = GTX 1080 at x8 with NVMe at x4 both Gen 3

non SLI m/b = GTX 1080 at x16 Gen 3, with NVMe at x2 Gen 2 using a Intel Z97 or other Intel 9 series boards.

 

[JoostinOnline]

5 minutes ago, ZenMonkey said:

 

Really? Interesting. I checked Intel's ARK listing and it just mentioned the 16 lanes so I thought I was screwed. That's good to know, but a second GPU, even if it only uses one or two lanes because it's dedicated to mining, would use those dedicated lanes, right?

A 1080 would run the same on a 4x 3.0 slot. 

[ZenMonkey]

2 minutes ago, Tiwaz said:

mining doesnt really care about lanes, many miners use cheap cpus and mobos and hook up gpus even to 1x slots with extension cables. For video production or gaming you should try to stick with at least PCIE 2.0 16x or 3.0 8x

note that SLI requires each card to run at least at 16x

 

I only have my primary computer, and I know mining only uses like a single lane, but I upgraded my video card so I currently have a spare that I've thought about using for mining. I also have an NVMe slot that I'd like to use in the future. But I wanted to make sure it didn't impact my normal use or gaming before doing anything. Consensus seems to be that I won't notice a difference. Thanks everyone!

[ZenMonkey]

5 minutes ago, JoostinOnline said:

A 1080 would run the same on a 4x 3.0 slot. 

 

Off topic but out of curiosity... why do they make them 16 lane cards if they only need 4 to run normally?

[JoostinOnline]

13 minutes ago, ZenMonkey said:

 

Off topic but out of curiosity... why do they make them 16 lane cards if they only need 4 to run normally?

Depends on the PCIe generation. They have different bandwidths. 

[Tiwaz]

34 minutes ago, ZenMonkey said:

 

Off topic but out of curiosity... why do they make them 16 lane cards if they only need 4 to run normally?

future proofing and sometimes more than 4x 3.0 would be beneficial but mostly not