chipset I need help with the PCIE Lanes on the CPU and the Chipset

[Antoniopap]

Hi I am building a new high end pc. Correct me if I'm wrong, but I believe that for LGA 1151, the chipset Z170 is the best. For LGA 2011 v3, I believe that X99 is the best.

I was thinking of buying the Intel core i7 6700k, which according to ark.intel.com, says it supports 16 pcie lanes. I know that this DOES NOT mean you can use 16 'pcie 3.0 x16' slots on your motherboard at the same time.

Correct me if I'm wrong again, but to my knowledge I know it means that for one of those pcie 3.0 x16 slots, it will take 16 lanes from the cpu, leaving 0 available on the i7 6700k (I know the 6800k has 28 lanes).

How do people use SLI then? Do expansion cards, gpus, and other items in the pcie slots only use the amount that they need at the time (I know that you can put 1x cards into a 16x slot, but I mean a gpu that needs an 8x slot will sometimes only be using 4x when under a small load)? If a gpu only need an 8x slot, and you have 3 gpus in sli, wouldn't that be using 24 lanes? How do people use cpus with the default 16 pcie lanes for a 3 gpu sli config? When the chipset comes in, for the Z170, it says:  Processor PCIe Configuration - 1x16 or 2x8 or 1x8+2x4. This is for Z170, and the highest cpu I found, i7 6700k, only supports 16 pcie lanes, this makes sense. But why does the Asus Z170-A motherboard have 3 pcie 3.0 x16 slots? Under that information, it also said:  Chipset PCI-E Lanes (Gen) - *20(3.0). I don't know what this means. Could this mean how many pcie lanes the chipset supports? This number is high, but could there be a time when the chipset bottlenecks the cpu through pcie lanes? Please answer all questions throughout this paragraph. Thanks for the help!

[Glenwing]

6 minutes ago, Antoniopap said:

Hi I am building a new high end pc. Correct me if I'm wrong, but I believe that for LGA 1151, the chipset Z170 is the best. For LGA 2011 v3, I believe that X99 is the best.

I was thinking of buying the Intel core i7 6700k, which according to ark.intel.com, says it supports 16 pcie lanes. I know that this DOES NOT mean you can use 16 'pcie 3.0 x16' slots on your motherboard at the same time.

Correct me if I'm wrong again, but to my knowledge I know it means that for one of those pcie 3.0 x16 slots, it will take 16 lanes from the cpu, leaving 0 available on the i7 6700k (I know the 6800k has 28 lanes).

How do people use SLI then? Do expansion cards, gpus, and other items in the pcie slots only use the amount that they need at the time (I know that you can put 1x cards into a 16x slot, but I mean a gpu that needs an 8x slot will sometimes only be using 4x when under a small load)? If a gpu only need an 8x slot, and you have 3 gpus in sli, wouldn't that be using 24 lanes? How do people use cpus with the default 16 pcie lanes for a 3 gpu sli config? When the chipset comes in, for the Z170, it says:  Processor PCIe Configuration - 1x16 or 2x8 or 1x8+2x4. This is for Z170, and the highest cpu I found, i7 6700k, only supports 16 pcie lanes, this makes sense. But why does the Asus Z170-A motherboard have 3 pcie 3.0 x16 slots? Under that information, it also said:  Chipset PCI-E Lanes (Gen) - *20(3.0). I don't know what this means. Could this mean how many pcie lanes the chipset supports? This number is high, but could there be a time when the chipset bottlenecks the cpu through pcie lanes? Please answer all questions throughout this paragraph. Thanks for the help!

If multiple PCIe devices are in use, the lanes will be split between them in the configuration specified. Triple graphics cards will run in x8 / x4 / x4, meaning the first card will have 8 lanes, the second will have 4, and the third will have 4, for a total of 16.

 

The Z170 chipset supports an additional 20 PCIe 3.0 lanes in addition to the 16 provided by the CPU, for a total of 36, but the ones provided by the chipset are auxiliary lanes and are used for x1 slots as well as devices embedded in the motherboard already (USB control chips, etc.). The auxiliary lanes generally aren't used for main x16 slots, once in a while they may be used for the bottom x4 slot.

[Antoniopap]

Thanks for the help. So isn't the first gpu that gets the most lanes the closest to the cpu. Also, I thought that SLI needs at least 8 lanes per gpu?

[Lubi97]

3 minutes ago, Antoniopap said:

Thanks for the help. So isn't the first gpu that gets the most lanes the closest to the cpu. Also, I thought that SLI needs at least 8 lanes per gpu?

That is true. For Nvidia cards you need at least 8 Lanes per card, which is why only 2-way SLI is possible with a 6700K.

(That is one of the reasons some people go to X99. For instance if you want 2-way SLI, PCIe SSD and a PCIe Ethernet-card it gets kind of tight for any other expansion card.)

For AMD cards the limit is 4 Lanes, which would make 3-way Crossfire possible.

[Zyndo]

2 minutes ago, Antoniopap said:

Thanks for the help. So isn't the first gpu that gets the most lanes the closest to the cpu. Also, I thought that SLI needs at least 8 lanes per gpu?

on 16 PCIe lanes of skylake/Z170 you can only run 2-way SLI. that is, 2 Nvidia cards connected via SLI bridge with SLI mode enabled. Nvidia requires no less than 8 lanes per GPU in order to run in SLI mode, therefore you need 16 lanes for 2way, 24 lanes for 3way, 32 lanes for 4way. (3 and 4-way don't really exist anymore)

 

 

I think the thing you are confused about is that not every multi-GPU setup is SLI. You could put 3 AMD GPU's into your Z170 motherboard and run 3-way crossfire with 8+4+4 (crossfire is AMD's equivalent to SLI, but its not the same. they only require 4 lanes per GPU in order to Crossfire). There are also things like running LDA/MDA modes on your GPU's. Running them individually as compute GPU's or PhysX units. There are probably many other applications I don't know of for GPU's like that.

 

 

Bottom line is that there are so many other things you can do with GPU's other than strictly SLI, so the motherboard has increased options in case you wanted to explore some of them.

[Antoniopap]

1 minute ago, Lubi97 said:

That is true. For Nvidia cards you need at least 8 Lanes per card, which is why only 2-way SLI is possible with a 6700K.

(That is one of the reasons some people go to X99. For instance if you want 2-way SLI, PCIe SSD and a PCIe Ethernet-card it gets kind of tight for any other expansion card.)

For AMD cards the limit is 4 Lanes, which would make 3-way Crossfire possible.

I didn't know you could do 3-way crossfire. I know there is MDA mode when SLI is disabled, is there other things for amd besides crossfire. I have an RX 480 Nitro + 4GB and I want to get a second one, but Crossfire is buggy

[Glenwing]

8 minutes ago, Antoniopap said:

Thanks for the help. So isn't the first gpu that gets the most lanes the closest to the cpu. Also, I thought that SLI needs at least 8 lanes per gpu?

Depends on however the motherboard manufacturer configures it, but generally yes the first slot gets 8 lanes when multiple cards are attached.

 

Yes SLI does need 8 lanes per card, but this restriction can be disabled with driver hacks, and you can have multi-GPU configurations without enabling SLI, for example for rendering, adding more outputs for monitors, etc. Also CrossFire doesn't have the x8 restriction at all.

[Lubi97]

1 minute ago, Antoniopap said:

I didn't know you could do 3-way crossfire. I know there is MDA mode when SLI is disabled, is there other things for amd besides crossfire. I have an RX 480 Nitro + 4GB and I want to get a second one, but Crossfire is buggy

Sorry, I can't help you with that, I don't have any deeper knowledge of AMD cards and Crossfire. 

[Antoniopap]

 

6 minutes ago, Lubi97 said:

Sorry, I can't help you with that, I don't have any deeper knowledge of AMD cards and Crossfire. 

Its okay, I don't know much either.

 

6 minutes ago, Glenwing said:

Depends on however the motherboard manufacturer configures it, but generally yes the first slot gets 8 lanes when multiple cards are attached.

 

Yes SLI does need 8 lanes per card, but this restriction can be disabled with driver hacks, and you can have multi-GPU configurations without enabling SLI, for example for rendering, adding more outputs for monitors, etc. Also CrossFire doesn't have the x8 restriction at all.

I heard of some of those modes, there are MDA mode, LDA explicit, and LDA inplicit. Can you explain all of them for me, I saw them in one of Linus's videos, but he didn't go into enough detail. Can you game out of SLI, and will there be a performance increase? How will it stack up against SLI in performance. Can you render fast in SLI too. Are there any other modes for AMD that aren't crossfire?

[Glenwing]

1 minute ago, Antoniopap said:

I heard of some of those modes, there are MDA mode, LDA explicit, and LDA inplicit. Can you explain all of them for me, I saw them in one of Linus's videos, but he didn't go into enough detail. Can you game out of SLI, and will there be a performance increase? How will it stack up against SLI in performance. Can you render fast in SLI too. Are there any other modes for AMD that aren't crossfire?

I think those are multi-GPU gaming modes which can be used with DirextX 12, I don't know much about them. Outside of DX12, you can't do multi-GPU gaming without SLI / CFX. Gaming without enabling SLI will just use one graphics card, and the others won't be used. But like I said there are other things to do besides gaming. I have two graphics cards and I use one dedicated to encoding video so I can record gameplay with GPU acceleration without impacting performance at all.

[Antoniopap]

2 minutes ago, Glenwing said:

I think those are multi-GPU gaming modes which can be used with DirextX 12, I don't know much about them. Outside of DX12, you can't do multi-GPU gaming without SLI / CFX. Gaming without enabling SLI will just use one graphics card, and the others won't be used. But like I said there are other things to do besides gaming. I have two graphics cards and I use one dedicated to encoding video so I can record gameplay with GPU acceleration without impacting performance at all.

What is GPU acceleration? And do you mean you can record gaming while having one gpu do the recording, while the other processes the game? Do you need to do any setting up for this mode. For crossfire, it is bridgeless, so do I have to enable crossfire in the setup? And if I don't, will it be in this no crossfire mode that you have? Have gpus do you have? Thanks

[Glenwing]

4 minutes ago, Antoniopap said:

What is GPU acceleration?

GPU acceleration means that computation tasks which are normally done by the CPU are offloaded to be performed by the GPU instead.

4 minutes ago, Antoniopap said:

And do you mean you can record gaming while having one gpu do the recording, while the other processes the game? Do you need to do any setting up for this mode. 

Yes. Depends on what software you use, I use OBS. It always uses the first GPU for encoding, there is no way to select which one is used, but I discovered if I plug all my monitors into the second graphics card, that one is used for processing all the games while the first GPU is left idle and only used for the video encoding. There is no special set up or software configuration that needs to be done though.

4 minutes ago, Antoniopap said:

For crossfire, it is bridgeless, so do I have to enable crossfire in the setup? And if I don't, will it be in this no crossfire mode that you have? Have gpus do you have? Thanks

No, you don't need to enable CrossFire if you don't want to. CrossFire/SLI isn't synonymous with "multiple graphics cards", it's just a mode that allows them to work together in a certain way, specifically designed for games, because that requires close synchronization. Outside of games, CrossFire/SLI is generally not needed for multiple GPUs to be utilized. You don't need any other kind of special "multi-GPU mode" to use in place of CrossFire/SLI if you decide to disable those. If you disable CrossFire/SLI then your graphics cards will all still work fine as independent devices which can be used by applications for whatever.

[Antoniopap]

Forget this post here. I moved it down to the other one. I forgot to quote you in it and I don't know how to add a quote when editing. 

Edited August 29, 2016 by Antoniopap
I forgot to quote you

[Antoniopap]

9 minutes ago, Glenwing said:

GPU acceleration means that computation tasks which are normally done by the CPU are offloaded to be performed by the GPU instead.

Yes. Depends on what software you use, I use OBS. It always uses the first GPU for encoding, there is no way to select which one is used, but I discovered if I plug all my monitors into the second graphics card, that one is used for processing all the games while the first GPU is left idle and only used for the video encoding. There is no special set up or software configuration that needs to be done though.

No, you don't need to enable CrossFire if you don't want to. CrossFire/SLI isn't synonymous with "multiple graphics cards", it's just a mode that allows them to work together in a certain way, specifically designed for games, because that requires close synchronization. Outside of games, CrossFire/SLI is generally not needed for multiple GPUs to be utilized. You don't need any other kind of special "multi-GPU mode" to use in place of CrossFire/SLI if you decide to disable those. If you disable CrossFire/SLI then your graphics cards will all still work fine as independent devices which can be used by applications for whatever.

First things first, how did you quote parts of what I wrote? Next, I know that NVIDIA Shadowplay is a really good recorder, and I used to have it with my old GTX 750 ti, now I have the RX 480. The recorder software that comes with the Rx 480 isn't that good. With your special setup, and using OBS, will it be just as fast as Shadowplay? Because sometimes I use OBS and it can be laggy. So, when using GPU acceleration or things like video rendering, is it faster than a cpu? Would a gpu acceleration be a better choice than buying a faster cpu? Also, when not using Crossfire or SLI, could I put my old GTX 750 ti in the same rig as my RX 480, and use the 750 ti for the video encoding, while using the RX 480 for gaming?

[Glenwing]

5 minutes ago, Antoniopap said:

First things first, how did you quote parts of what I wrote?

Manually, by quoting you multiple times and erasing text inside each quote

5 minutes ago, Antoniopap said:

First things first, how did you quote parts of what I wrote? Next, I know that NVIDIA Shadowplay is a really good recorder, and I used to have it with my old GTX 750 ti, now I have the RX 480. The recorder software that comes with the Rx 480 isn't that good. With your special setup, and using OBS, will it be just as fast as Shadowplay? Because sometimes I use OBS and it can be laggy.

Yes, it should be just as fast. Under encoding settings OBS lets you select which encoder you want to use, x264 (CPU) or NVENC (NVIDIA GPU), although like I said it doesn't let you select which GPU to use if you have more than one. When I use CPU, I could only set it to mediocre image quality before getting frame drops, and with NVENC (when I recorded on the same GPU as the game was running on) the recordings would have massive frame drops in games that maxed out my GPU. But now using my secondary GPU for games, I use NVENC option without any frame drops. So, it works pretty well at least in my experience.

10 minutes ago, Antoniopap said:

So, when using GPU acceleration or things like video rendering, is it faster than a cpu? Would a gpu acceleration be a better choice than buying a faster cpu?

Yes, but GPUs are only partially used, when rendering with things like Adobe Premiere Pro. A lot of the work is still done on the CPU, the GPU is just used to accelerate the process. It is not a complete replacement, and a faster CPU will still be useful.

11 minutes ago, Antoniopap said:

Also, when not using Crossfire or SLI, could I put my old GTX 750 ti in the same rig as my RX 480, and use the 750 ti for the video encoding, while using the RX 480 for gaming?

Yes that should work fine, although I've never tested it. Just make sure you put the 750 Ti on top if you want to use it for the recording.

[Antoniopap]

4 minutes ago, Glenwing said:

Just make sure you put the 750 Ti on top if you want to use it for the recording.

What do you mean by put the 750 Ti on top. Since I will have an AMD Gpu and an NVIDIA Gpu, won't there be a name called AMD and a name called NVIDIA? How would it be if I put the 750 ti in a 1x port just for encoding? I don't think that would even work tho

[Glenwing]

3 minutes ago, Antoniopap said:

What do you mean by put the 750 Ti on top. Since I will have an AMD Gpu and an NVIDIA Gpu, won't there be a name called AMD and a name called NVIDIA? How would it be if I put the 750 ti in a 1x port just for encoding? I don't think that would even work tho

Yeah I guess since you don't have two NVIDIA cards it wouldn't matter.

 

Most x1 slots have a sealed back which prevents longer cards from being placed inside, and it would probably limit your recording even if you could.

[Antoniopap]

Thanks for the help! Also, can I have some recommendations on the Z170 motherboards I like the Asus Z170-A

 

[Antoniopap]

15 minutes ago, Glenwing said:

Yeah I guess since you don't have two NVIDIA cards it wouldn't matter.

 

Most x1 slots have a sealed back which prevents longer cards from being placed inside, and it would probably limit your recording even if you could.

I figured out how to use the AMD card as a video encoder! Nvidia NVENC is the feature I think you were using for video encoding. That is nvidia's video encoding software. Amd VCE is the same thing, but for AMD. There is an addon to OBS that adds AMD VCE to the options, so I can video encode with my rx 480. Also, what is CBR and CBR Padding? And is it easy to switch from SLI to non SLI. I know that you need a bridge for SLI, so do you have to remove it. And, for crossfire there is no bridge, so it is seamless to disconnect from crossfire and to enable it? Are there reboots on your computer or does it blackscreen for a second? Thanks!

[Antoniopap]

22 minutes ago, Glenwing said:

Yeah I guess since you don't have two NVIDIA cards it wouldn't matter.

 

Most x1 slots have a sealed back which prevents longer cards from being placed inside, and it would probably limit your recording even if you could.

https://obsproject.com/forum/threads/obs-studio-amd-vce-bitrate-problem.45454/

The top picture of this link has the AMD VCE added as a plugin. Also, what is Quick Sync?

[Glenwing]

1 minute ago, Antoniopap said:

https://obsproject.com/forum/threads/obs-studio-amd-vce-bitrate-problem.45454/

The top picture of this link has the AMD VCE added as a plugin. Also, what is Quick Sync?

Cool. I didn't know whether that option would appear or not if you had an AMD card, I've never tried it before.

 

QuickSync is using Intel integrated graphics for encoding.

[Antoniopap]

Just now, Glenwing said:

Cool. I didn't know whether that option would appear or not if you had an AMD card, I've never tried it before.

 

QuickSync is using Intel integrated graphics for encoding.

Thanks! BTW I'm building a new pc, but for the moment I am using my RX 480 in this computer. When my new pc is finished, I will move it over. For now, I have the i3 4170. I know it has integrated graphics. Why doesn't this feature showup?

[Glenwing]

I don't know. I see the option for Quick Sync even on my system (i7-3930K) which doesn't have integrated graphics, it's just greyed out. I don't think I've seen it gone altogether before. Not that I have a ton of experience with OBS though.