How many Lane does a typical Nvidia video card really uses up?

Happy Hopping

Happy Hopping

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on any video card, their sys. requirement is a x16 SLOT. But that's the SLOT length.

How many lane does it really need though? Does it require Gen 3 x 4, Gen 3 x 8 or Gen 3 x 16? And is there a website that tells you how many lane each video card really use up?

my video card is a GTX 650 Ti boost, I'm trying to figure out the exact no. of lane that it's really using up
 
Generally 8.

That's why the min requirement for SLI is 8x/8x. From everything I have read, the difference between running 8x and 16x is barely a couple of percent.
 
Too many variables to make a website that can answer that question. It depends on the application, the GPU, screen resolution, etc. For example, certain games transfer a lot of information between the GPU and CPU, and will become bottlenecked with less lanes. Other games do not. Compute on the GPU generally requires more bandwidth than gaming. More powerful cards generally require more bandwidth. SLI will require more bandwidth as data needs to be shared between GPUs. Higher resolutions require more bandwidth than lower resolutions.

Here is [H]OCP's study on the matter a few years ago: https://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4/

GTX 480 SLI is not held back by PCI-E 2.0 x4/x4 at 2560x1600. A GTX 480 is slightly more powerful than a GTX 650 Ti Boost. Extrapolating from that, I would assume a single GTX 650 Ti Boost would not need more than PCI-E 3.0 x2 (equivalent to 2.0 x4) in gaming.
 
Happy Hopping said:
on any video card, their sys. requirement is a x16 SLOT. But that's the SLOT length.

How many lane does it really need though? Does it require Gen 3 x 4, Gen 3 x 8 or Gen 3 x 16? And is there a website that tells you how many lane each video card really use up?

my video card is a GTX 650 Ti boost, I'm trying to figure out the exact no. of lane that it's really using up
Click to expand...
You might want to rephrase that question in your thread title. It's not so much about how many it will use, it's how many it needs. Your question here does clarify it somewhat.

The neat thing about PCI Express is the device will use as many lanes as you give it up to it's designed specifications. You can plug a video card with a x16 slot into a x1 slot and it will likely work. It won't work well, but it will likely work. This is assuming the x1 slot is open ended and the remaining piece of the video card can stick out. A video card will use all 16 lanes. Whether it uses those 16 lanes to their full potential is a different matter altogether.
 
First of all, I don't have SLI and never will, don't have $ for more than 1 video card. I do have a few games in my SSD, but never have time to play them. The only game that I play daily is a bubble game on facebook

But I am running at 4K video resolution and do watch video on my 2nd monitor, which is only 1920 x 1080.

As to bandwidth, in the last generation lane implementation and video card bandwidth, I learned that they never really make a video card that max. out the lane bandwidth. So I always assume that even w/ this generation video card, the bandwidth at x16 is so high that no video card can max it out. I never play a game on UHD resolution before, so I don't really know.

As to Kyle's research, what he said about " This was good news for people with newer systems that want to move video cards further apart for cooling reasons or were forced to run in this mode due to other devices taking up PCIe lanes or motherboard limitations." is exactly the reason I post the above question

Now, how does Kyle perform the test? How can you control the no. of lane on a video card? and set it to x8 and x16?
 
It will use as many lanes as you give it, but the question really is if it will use all of the available bandwidth.
Happy Hopping said:
First of all, I don't have SLI and never will, don't have $ for more than 1 video card. I do have a few games in my SSD, but never have time to play them. The only game that I play daily is a bubble game on facebook

But I am running at 4K video resolution and do watch video on my 2nd monitor, which is only 1920 x 1080.

As to bandwidth, in the last generation lane implementation and video card bandwidth, I learned that they never really make a video card that max. out the lane bandwidth. So I always assume that even w/ this generation video card, the bandwidth at x16 is so high that no video card can max it out. I never play a game on UHD resolution before, so I don't really know.

As to Kyle's research, what he said about " This was good news for people with newer systems that want to move video cards further apart for cooling reasons or were forced to run in this mode due to other devices taking up PCIe lanes or motherboard limitations." is exactly the reason I post the above question

Now, how does Kyle perform the test? How can you control the no. of lane on a video card? and set it to x8 and x16?
Click to expand...
Most motherboards allow you to change the PCI-E settings in their BIOS. A motherboard will also automatically change how PCI-E lanes are distributed based on the hardware plugged in.

Why do you need to know how many lanes your video card is using, anyway?
 
Covering up the pins is how they (and other sites) test it. PCI-E pinout is publicly available.

However, even if you cover them up, if your motherboard does not have the hardware to switch the lanes to other slots (i.e. SLI motherboard), you wouldn't be able to use the lanes. If your motherboard could do it, it'll automatically allocate lanes depending on what you plug in. Essentially, it's an interesting thought exercise but has zero practical usage.
 
First of all, it's BANDWIDTH, not LANES.

a PCIE 2.0 x16 slot has TWICE the bandwidth of a PCIe 1.0 16x slot.
a PCIE 3.0 x16 slot has TWICE the bandwidth of a PCIe 2.0 16x slot.

And along those same lines:

a PCIE 3.0 x16 slot has TWICE the bandwidth of a PCIe 3.0 8x slot.

SIMPLE RULES:

Half the number of lanes = half the bandwidth.
Reducing the version number by 1 = half the bandwidth.

Cards will run at whatever speed your slot supports.


Second of all, THE BANDWIDTH DEMANDS DEPENDS ON THE GAME Some games use more bandwidth than others.

Just see this review, where some games are hardly affected by dropping the bandwidth to 1/4, while others take a huge performance hit:

https://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_1080_PCI_Express_Scaling/3.html

Unfortunately, this means there's no simple answer to "how many lanes do you need." Luckily they make this easy by making top motherboard slots 16 lanes, except on higher-end SLI motherboards.

You also need a lot less lanes if you're not gaming.
 
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very useful informat
Armenius said:
It will use as many lanes as you give it, but the question really is if it will use all of the available bandwidth.

Most motherboards allow you to change the PCI-E settings in their BIOS. A motherboard will also automatically change how PCI-E lanes are distributed based on the hardware plugged in.

Why do you need to know how many lanes your video card is using, anyway?
Click to expand...

because my video card, a double width 650 GTX Ti, is on the SECOND Slot of my motherboard, and my motherboard has 4 x x16 slot + (x16 lane EACH) , it's Z8PE, $600 motherboard. The reason it's not the on 1st x16 slot is because the Noctua giant 14 in. CPU Cooler is blocking it.

But my upcoming motherboard is only x16 (x16 lane) on the FIRST slot, the rest is x8 lane, so I need to know what will happen if I install my video card on the x8 lane.

=================================

Whateverer: I thought the 2nd "x", we called it a "lane", don't we? You're saying we called it x8 bandwidth? Anyhoo, very useful information, that's what I want to know, is that different games take up different bandwidth.
 
Happy Hopping said:
very useful informat


because my video card, a double width 650 GTX Ti, is on the SECOND Slot of my motherboard, and my motherboard has 4 x x16 slot + (x16 lane EACH) , it's Z8PE, $600 motherboard. The reason it's not the on 1st x16 slot is because the Noctua giant 14 in. CPU Cooler is blocking it.

But my upcoming motherboard is only x16 (x16 lane) on the FIRST slot, the rest is x8 lane, so I need to know what will happen if I install my video card on the x8 lane.

=================================

Whateverer: I thought the 2nd "x", we called it a "lane", don't we? You're saying we called it x8 bandwidth? Anyhoo, very useful information, that's what I want to know, is that different games take up different bandwidth.
Click to expand...
I take it your upcoming motherboard has PCI-E Gen3? If that is the case, then 8 lanes is enough. I had no performance issues with my GTX Titan X when feeding it only 8 Gen3 lanes.

whateverer is being pedantic. The amount of bandwidth is determined by the number of lanes that are made available to the hardware, so you're both technically correct. In PCI-E Gen3 the bandwidth is about 1 GB/s bidirectional per lane, so 8 lanes will have a gross bandwidth of 16 GB/s.
 
Happy Hopping said:
very useful informat


because my video card, a double width 650 GTX Ti, is on the SECOND Slot of my motherboard, and my motherboard has 4 x x16 slot + (x16 lane EACH) , it's Z8PE, $600 motherboard. The reason it's not the on 1st x16 slot is because the Noctua giant 14 in. CPU Cooler is blocking it.

But my upcoming motherboard is only x16 (x16 lane) on the FIRST slot, the rest is x8 lane, so I need to know what will happen if I install my video card on the x8 lane.

=================================

Whateverer: I thought the 2nd "x", we called it a "lane", don't we? You're saying we called it x8 bandwidth? Anyhoo, very useful information, that's what I want to know, is that different games take up different bandwidth.
Click to expand...

Every slot has a base speed, based on the REVISION NUMBER:

PCIe 1 = Gen1 = 250 MB/s per-lane
PCIe 2 = Gen2 = 500 MB/s per-lane
PCIe 3 = Gen3 = 1,000 MB/s per-lane,

Now take the number of lanes and multiply it by the base speed. That is the TOTAL BANDWIDTH FOR THE SLOT: Some examples:


PCIe 1 = 250 MB/s per-lane, an 8 lane slot (x8 link) = 8 x 250 MB/s = 2000 MB/s

PCIe 2 = 500 MB/s per-lane, a 4 lane slot (x4 link) = 4 x 500 MB/s = 2000 MB/s

PCIe 3 = 1,000 MB/s per-lane, a 16 lane slot (x16 link) = 16 x 1,000 MB/s /s = 16,000 MB/s/


IMPORTANT NOTE: there are lots of x16-SIZED SLOTS with less than 16 lanes. They make the slot larger for greater compatibility with more devices, but don't always have enough lanes for every "16-lane" slot.

This is your motherboard configuration:


Slot Location 3: PCI-E x16 (Gen2 X8 Link)
Slot Location 4: PCI-E x16 (Gen2 X8 Link)
Slot Location 5: PCI-E x16 (Gen2 X8 Link)
Slot Location 6: PCI-E x16 (Gen2 X16 Link), Auto switch to x8 link if slot 5 is occupied
Click to expand...

So Every slot except the bottom one is 8 lanes, with each LANE running at 500 MB/s.

THE BOTTOM SLOT HAS TWICE THE BANDWIDTH OF ANY OTHER, if it's the only one you're using.

You can find detailed bandwidth information for each slot on the newegg product page under specs
 
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okay, once again, thank you, all of you. In the end, I'm just trying to save $ on the next motherboard
 
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