Skylake & Haswell-E PCIe lane misconception

[Deoros]

On ‎06‎/‎10‎/‎2015 at 5:00 PM, Glenwing said:

 

Do note that the lower-end chipsets, eg. H110, cut down on the PCIe connectivity on offer.

Great post by the way. This really needed addressing as it's an extremely wide misconception. I am going to pin this thread for a while.

So I should be able to have the 1080 GPU and a M.2 SSD without any power loss?

[Undertow_]

On 10/6/2015 at 5:42 AM, JebKerman said:

I dunno about that, they found in the video that, for a similar system (same RAM, ASUS -A series board for appropriate socket), X99 is more expensive than Z170 by about $100 USD. They trade places in games (game dependent, oddly enough Cities: Skylines performed considerably better on the 6700K). the 5820K only truly won in some synthetic benchmarks.

 

I'd say Z170 wins for the majority of consumers (ok, maybe prosumers)

Any sources to back up the numbers?

[brighttail]

All I know is my i7-5930k supposedly has 40 pci-e x3 lanes. I have two GPUs running at 16 each and two m.2 running at x4 each in RAID 0.

 

I don't think a z170 could do that. Could it?  So the extra cash makes it worth while in my configuration.

 

I think the z170 would run them at x8, x8 and x4 - x4.

[Lurick]

So if I'm reading this right the chipset can have up to 20 PCIe 3.0 lanes but it's communication with the CPU is only done over what is essentially 4 PCIe 3.0 lanes. So if I had lets say two graphics cards in SLI, a PCIe 8x 10Gb NIC card, and a x4 NVMe drive, would I notice any bottlenecks or issues?

[Bajantechnician]

1 hour ago, Lurick said:

So if I'm reading this right the chipset can have up to 20 PCIe 3.0 lanes but it's communication with the CPU is only done over what is essentially 4 PCIe 3.0 lanes. So if I had lets say two graphics cards in SLI, a PCIe 8x 10Gb NIC card, and a x4 NVMe drive, would I notice any bottlenecks or issues?

i believe that your nic card would run slower, or a gpu would not work. nvidia requires 8x for sli

[Lurick]

Just now, Bajantechnician said:

i believe that your nic card would run slower, or a gpu would not work. nvidia requires 8x for sli

Alright, that's what I was thinking so I guess I'll just stick with the x99 and Broadwell-E route I had planned

 

[Bajantechnician]

Just now, Lurick said:

Alright, that's what I was thinking so I guess I'll just stick with the x99 and Broadwell-E route I had planned

 

yeah

for x99 id recommend a 5930x, as it has 40 lannes, which is ~10 more lanes you dont need, that you can use in the future.

the 5820k only has 28 lanes.

 

i have a 5820k, running 3 way 390x, and a m.2 drive.

 

to 8x x3 + 4 =28. exactly

and i dont plan on putting in more cards, so im all set

[Lurick]

Just now, Bajantechnician said:

yeah

for x99 id recommend a 5930x, as it has 40 lannes, which is ~10 more lanes you dont need, that you can use in the future.

the 5820k only has 28 lanes.

 

i have a 5820k, running 3 way 390x, and a m.2 drive.

 

to 8x x3 + 4 =28. exactly

and i dont plan on putting in more cards, so im all set

Yup, that was the plan but with the Broadwell refresh coming in just a couple weeks I want to see what the 6800K has to offer for PCIe lanes as it might have more than the 5820K but be priced around that same area. If not then Ill go with the 6850K which should have the 40 lanes.

[Bajantechnician]

5 minutes ago, Lurick said:

Yup, that was the plan but with the Broadwell refresh coming in just a couple weeks I want to see what the 6800K has to offer for PCIe lanes as it might have more than the 5820K but be priced around that same area. If not then Ill go with the 6850K which should have the 40 lanes.

yup lol

well, good luck

[brighttail]

11 hours ago, Lurick said:

So if I'm reading this right the chipset can have up to 20 PCIe 3.0 lanes but it's communication with the CPU is only done over what is essentially 4 PCIe 3.0 lanes. So if I had lets say two graphics cards in SLI, a PCIe 8x 10Gb NIC card, and a x4 NVMe drive, would I notice any bottlenecks or issues?

I have a 40 pci-e CPU.  I have two GTX 980's running at x16, x16.  I have two Samsung pro 950s running in raid at x4.    If I add one more card that runs in x4, my M.2s slow to x2 speed.  So I would imagine that your NVMe drive might go down to x2. It would be close.

[bobman279]

On 07/10/2015 at 1:24 AM, Glenwing said:

You literally will have enough. Pascal will use nowhere near the max bandwidth of x16 in gaming and it's doubtful it will even be bottlenecked by gen3 x4. PCIe usage is mainly dependent on the application, not so much the power of the graphics card, and games use relatively low amounts of bandwidth.

The GPUs will run in Gen3 x8/x8 which is more than enough, and any additional devices like M.2 SSDs will run through the chipset without having any effect on the GPUs at all.

it doesn't matter on the build or architecture. Textures, video and pictures take a fair amount of bandwidth.

[AndyKala]

On 10/6/2015 at 3:29 AM, Sakkura said:

 

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

 

X99 will almost certainly remain the same for Broadwell-E.

So, does this mean that it's a total of 36 Gen 3 PCIe lanes for Z170?

[AndyKala]

On 5/15/2016 at 6:38 PM, brighttail said:

All I know is my i7-5930k supposedly has 40 pci-e x3 lanes. I have two GPUs running at 16 each and two m.2 running at x4 each in RAID 0.

 

I don't think a z170 could do that. Could it?  So the extra cash makes it worth while in my configuration.

 

I think the z170 would run them at x8, x8 and x4 - x4.

Gen 8x PCIe lanes is more than enough for a GPU, so running at x8 is just fine for SLI.

[Sakkura]

9 hours ago, AndyKala said:

So, does this mean that it's a total of 36 Gen 3 PCIe lanes for Z170?

Yes, but the 20 lanes on the chipset are still subject to the DMI 3.0 limit. 

[TheProfosist]

16 hours ago, Sakkura said:

Yes, but the 20 lanes on the chipset are still subject to the DMI 3.0 limit. 

thank you for clarifying your answer because many people wouldnt. Also the DMI limit is basically PCI-E 3.0 x4.

 

[AndyKala]

On 10/6/2015 at 3:29 AM, Sakkura said:

 

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

 

X99 will almost certainly remain the same for Broadwell-E.

Can I run an SLI setup 8x, and 8x, 1 wifi card 1x, and a NVME drive x4 without any bottlenecks?

[Sakkura]

6 hours ago, AndyKala said:

Can I run an SLI setup 8x, and 8x, 1 wifi card 1x, and a NVME drive x4 without any bottlenecks?

Yes.

[Humble_newbie]

It more like this way,

 

You have PCI-e 3.0,2.0 and 1.0

You have x16,x4,1 lanes

 

Now no matter how many lanes you mobo or chipset has to offer, you are only going to use the lanes your CPU allows you to use.

For example: 

CASE 1:

I-5 6600k or i-7 6700k paired with Z170-Deluxe

Available lanes from CPU: 16

Available slots on mobo: 2x PCI-e x16 3.0,2.0

                                       1x PCI-e x4

                                        1x PCI-e x1

 

Which means in you plug in 1 GPU for example GTX 980 which individually use x16 3.0 bus,  you should be fine because then you CPU will dedicate its 16 lanes to the GPU.

It gets tricky when you connect, two GTX 980 in SLI, because you CPU only has 16 lanes to dedicate across available 32 lanes of total PCI-e 3.0 GPUS. This is when the bandwidth is scaled down to 8 lanes per GPU totaling 16 lanes for both GPUS instead of 32. Now the CPU can use both GPUs. If you add another x4 PCi-e setup to this setup, everything will be scaled down even further in order to accommodate or I dont even know why any one would do this?

 

But now lets talk about setup two.

CASE 2:

CPU: intel i7-5960x

Mobo: Asus x99 Deluxe-II

Available lanes from CPU: 40

Availabe expansion slots on mobo: 40-Lane CPU-4 x PCIe 3.0/2.0 x16

                                                                                 (single at x16, dual at x16/x16, triple at x16/x16/x8, quintuple at x8/x8/x8/x8/x8 mode) *¹
                                                         28-Lane CPU-3 x PCIe 3.0/2.0 x16 (x16, x16/x8, x8/x8/x8) *²
                                                         28-Lane CPU-1 x PCIe 2.0 x16 (x1 mode) 
                                                                                 1 x PCIe 2.0 x16 (max at x4 mode) *³
                                                                                 1 x PCIe 2.0 x1          

 

This should be self explanatory on this setup.

 

For everyday computing with a standard 2x SLI and SSD or m.2 setup. a 16x lane CPU will do just fine.

 

But if you want 3 way SLI, 3x PCI-e SSD in raid 5. a wifi card, and all that amazing good ness, then you need that 40 lanes of CPU power. Or else stay with 16 lanes.        

[TheProfosist]

On 6/14/2016 at 10:58 PM, AndyKala said:

Can I run an SLI setup 8x, and 8x, 1 wifi card 1x, and a NVME drive x4 without any bottlenecks?

On X99 yeah easily on Z170 all depends on how they laid out the slots.

 

[AndyKala]

On 10/6/2015 at 9:17 AM, NumLock21 said:

Even though the Intel Z170 chipset has plenty of lanes for m.2, pcie, and the lanes from the cpu can just go towards the gpus. The X99 cpu itself already has enough lanes to go around, so it doesn't matter if it's shared or not. Z170 chipset may be superior than X99 chipset, but the X99 itself is overall the superior platform.

On X99 you can run SLI at full x16/x16 and still have enough lanes for 2 Intel 750 SSD.*

*except when running on 5820K.

Why would you run the GPU's at x16 lanes anyway? x8 lanes at gen 3 for each is more than enough. x16 gen 3 and x8 gen 3 make almost no difference. Plus with DX12 being adapted now, lesser CPU's are going to perform the same as the 5930k. An i3 will perform the same as a high end extreme addition i7. X99 is becoming less, and less needed. 

[NumLock21]

16 minutes ago, AndyKala said:

Why would you run the GPU's at x16 lanes anyway? x8 lanes at gen 3 for each is more than enough. x16 gen 3 and x8 gen 3 make almost no difference. Plus with DX12 being adapted now, lesser CPU's are going to perform the same as the 5930k. An i3 will perform the same as a high end extreme addition i7. X99 is becoming less, and less needed. 

Go tell the big boys like nvidia that x99 is less needed. Do some research on why there are different segments of hardware for different customers before you make a idiot of yourself.

[AndyKala]

31 minutes ago, NumLock21 said:

Go tell the big boys like nvidia that x99 is less needed. Do some research on why there are different segments of hardware for different customers before you make a idiot of yourself.

Hey buddy, I know very well that X99 is a much more proconsumer chipset. If your going to do extreme 4k video editing, than hell, go buy the new 6950X. For an average consumer, such as me, Z170 is more than enough. My point being is Z170 is going to serve people well who don't have stacks of money to throw at X99. I was trying to say that X99 is overkill for any average consumer, especially because of DX12. 

[NumLock21]

1 hour ago, AndyKala said:

Hey buddy, I know very well that X99 is a much more proconsumer chipset. If your going to do extreme 4k video editing, than hell, go buy the new 6950X. For an average consumer, such as me, Z170 is more than enough. My point being is Z170 is going to serve people well who don't have stacks of money to throw at X99. I was trying to say that X99 is overkill for any average consumer, especially because of DX12. 

As humans, building gets taller, vehicles becomes faster, and we want to travel farther.

You can get a X99 with a $1,000 budget, and it gives you 6 cores. So why not join the enthusiast club. Z170 won't be enough for you.

 

[AndyKala]

20 minutes ago, NumLock21 said:

As humans, building gets taller, vehicles becomes faster, and we want to travel farther.

You can get a X99 with a $1,000 budget, and it gives you 6 cores. So why not join the enthusiast club. Z170 won't be enough for you.

 

Z170 is better for gaming, and X99 will be replaced in about a year. Currently, Skylake is a better choice for gamers. I for one, love X99, but I am scared of buying because I feel it is going to be replaced by X109 or Y01.

[brighttail]

With any Intel chip in 1-1 1/2 years it is replaced.  Yeah the x99 will be replaced within a year, great!  Does that mean that the current x99s will be obsolete?  Hell no.   The Z170 processors will be good for another 12-18 months and boom replaced.

 

So wait for the new ones, keep the old ones after the new ones come out...doesn't really hurt one way or the other except in your wallet.