lanes question

[Xino]

hello, i was thinking of running sli. with 2x 970. but i also got an nvme 4xline in my pcie port would that be possible for this motherboard, ga-z97x-gaming 5 (rev. 1.0) + i7-4770k

[newcbomb]

I dont know if this is true, but intel's website says that that CPU only has 16 Lanes. Meaning it would only support 1 GPU at Full Speed. But not 2. You could probably get the SSD to work with only 1 GPU. 

 

https://ark.intel.com/products/75123/Intel-Core-i7-4770K-Processor-8M-Cache-up-to-3_90-GHz

[Jurrunio]

NVMe drive will either not work or run at SATA speeds. Or NVMe drive works but SLI cant be enabled.

 

980Ti instead. Going SLI is not the best way to get more fps.

[Xino]

i have also been looking at that, also the motherboard has 16x lanes. but someone was talking about combining the lanes on mobo and cpu 16+16 with a total of 32 lanes. so i got confused when reading that. just wanted to conform that i didnt have the wrong idea.

[Xino]

4 minutes ago, Jurrunio said:

NVMe drive will either not work or run at SATA speeds. Or NVMe drive works but SLI cant be enabled.

 

980Ti instead. Going SLI is not the best way to get more fps.

not saying that i would do it just that i have been thinking about it, i explain why i have this question on the post above.

[Hiya!]

18 minutes ago, Xino said:

i have also been looking at that, also the motherboard has 16x lanes. but someone was talking about combining the lanes on mobo and cpu 16+16 with a total of 32 lanes. so i got confused when reading that. just wanted to conform that i didnt have the wrong idea.

Ok so your cpu support sli which it can run 1 x16,2 x8 or 1x8+2x4.

And z97 mobo has additional 8x chipset lanes.

So in total u have 24 lanes.

Your GPU will use direct cpu lanes instead of chipset.

And ur mobo has additional chipset lanes for Nvme drives or any pcie add on.

Everything will work just fine.

However u shouldn't do sli get a single powerful gpu if u can.

U should only do SLI if only there's no more powerful single GPU on the market like SLi'ing the 1080 ti.

Cause with single gpu u dont have to deal with diminishing returns.

I hope this helps also use quote next time so we can notice u.

[Lurick]

59 minutes ago, newcbomb said:

I dont know if this is true, but intel's website says that that CPU only has 16 Lanes. Meaning it would only support 1 GPU at Full Speed. But not 2. You could probably get the SSD to work with only 1 GPU. 

 

https://ark.intel.com/products/75123/Intel-Core-i7-4770K-Processor-8M-Cache-up-to-3_90-GHz

Incorrect. PCIE3.0 x8 is plenty of bandwidth even for a 1080Ti without bottlenecking.

OP can get two GPUs and an SSD to work since the NVME drive will pull from the chipset.

There might be a conflict or issue if the NVME drive pulls from the CPU lanes directly but most of the time they are wired to pull from the chipset (PCH) lanes.

[Jurrunio]

59 minutes ago, Xino said:

i have also been looking at that, also the motherboard has 16x lanes. but someone was talking about combining the lanes on mobo and cpu 16+16 with a total of 32 lanes. so i got confused when reading that. just wanted to conform that i didnt have the wrong idea.

Not correct. mobo doesnt give out PCIe lanes.

 

35 minutes ago, Hiya! said:

Ok so your cpu support sli which it can run 1 x16,2 x8 or 1x8+2x4.

And z97 mobo has additional 8x chipset lanes.

So in total u have 24 lanes.

Your GPU will use direct cpu lanes instead of chipset.

And ur mobo has additional chipset lanes for Nvme drives or any pcie add on.

Everything will work just fine.

However u shouldn't do sli get a single powerful gpu if u can.

U should only do SLI if only there's no more powerful single GPU on the market like SLi'ing the 1080 ti.

Cause with single gpu u dont have to deal with diminishing returns.

I hope this helps also use quote next time so we can notice u.

In fact, consumer CPUs all have 20 PCIe lanes. 4 of them are directed to the chipset for SATA ports, USB ports, ethernet etc. That leaves 16 lanes behind. Chipset lanes are different. They run much slower since everything is loaded to the 4 PCIe lanes. They act more like a supplementary bus, carrying everything PCIe lanes couldnt handle.

[Hiya!]

1 minute ago, Jurrunio said:

Not correct. mobo doesnt give out PCIe lanes.

 

In fact, consumer CPUs all have 20 PCIe lanes. 4 of them are directed to the chipset for SATA ports, USB ports, ethernet etc. That leaves 16 lanes behind. Chipset lanes are different. They run much slower since everything is loaded to the 4 PCIe lanes. They act more like a supplementary bus, carrying everything PCIe lanes couldnt handle.

4 of them? really? so why they didn't include it in the spec sheet that they have 20 lanes 16 is for Gpu and the other 4 is for chipset?

 

thats why i said for nvme drives or any other pcie add on cause they are slower and can adds latency but its about enough for an nvme.

[Jurrunio]

2 minutes ago, Hiya! said:

4 of them? really? so why they didn't include it in the spec sheet that they have 20 lanes 16 is for Gpu and the other 4 is for chipset?

 

thats why i said for nvme drives or any other pcie add on cause they are slower and can adds latency but its about enough for an nvme.

Because it just gets annoying to those not into hardware.

 

It slows down to a point in which much cheaper SATA SSDs can get similar speeds.

[Hiya!]

2 minutes ago, Jurrunio said:

Because it just gets annoying to those not into hardware.

 

It slows down to a point in which much cheaper SATA SSDs can get similar speeds.

ehh i think for those whose not into hardware wont understand pcie lanes at all.

 

Sata SSD can get similar speed to a x4 Nvme through chipset lanes? really? cause u just triggered my Bs detector *i meant no offense

[Jurrunio]

13 minutes ago, Hiya! said:

 

Sata SSD can get similar speed to a x4 Nvme through chipset lanes? really? cause u just triggered my Bs detector *i meant no offense

4

No. What I mean is that NVMe drives that are forced to run with chipset lanes will slow down to SATA SSDs speeds because of bandwidth limitations.

[Hiya!]

6 minutes ago, Jurrunio said:

No. What I mean is that NVMe drives that are forced to run with chipset lanes will slow down to SATA SSDs speeds because of bandwidth limitations.

Really? hmm i need to research this cause afaik most z mobo are tied to south bridge and most nvme are designed to use chipset lanes automatically although if they want they could make them use cpu lanes but idk if the latency from the chipset will reduce the speed to sata speed. but who am i to speak i am just 18 and barely knows anything about pc.

 

[Xino]

17 hours ago, Jurrunio said:

No. What I mean is that NVMe drives that are forced to run with chipset lanes will slow down to SATA SSDs speeds because of bandwidth limitations.

 

17 hours ago, Hiya! said:

Really? hmm i need to research this cause afaik most z mobo are tied to south bridge and most nvme are designed to use chipset lanes automatically although if they want they could make them use cpu lanes but idk if the latency from the chipset will reduce the speed to sata speed. but who am i to speak i am just 18 and barely knows anything about pc.

 

are you guys sure that the pcie ssd will be run over the chipset lanes, since i have a addin card because the m.2 port on the mobo only run sata speed ?

[Jurrunio]

2 hours ago, Xino said:

 

are you guys sure that the pcie ssd will be run over the chipset lanes, since i have a addin card because the m.2 port on the mobo only run sata speed ?

8

a bit confusing, but yes.

[Hiya!]

On 23/11/2017 at 1:56 PM, Xino said:

 

are you guys sure that the pcie ssd will be run over the chipset lanes, since i have a addin card because the m.2 port on the mobo only run sata speed ?

Almost NVME Drives are designed to run with CHIPSET LANES and i have to disagree if its gonna be at sata speed cause X4 has 10Gbps transfer while sata 3 is 6Gbps bandwidth.

And no your M.2 slot will not run in sata speed.

In theory but in practice u wont be able to see the difference in real world scenarios unless u benchmark it but NVME are superior for transfering large sized data at once.

Here's the specs quoted from the manufacturer

Spoiler

1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.

 

1 x PCI Express x16 slot, running at x8 (PCIEX8)
* The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.

 

1 x PCI Express x16 slot, running at x4 (PCIEX4)
* The PCIEX4 slot shares bandwidth with all PCI Express x1 slots. All PCI Express x1 slots will become unavailable when a PCIe x4 expansion card is installed.

As u can see u can SLI 970 and still running the NVME drives at Pcie x4 speed

[Xino]

On 24/11/2017 at 1:56 PM, Hiya! said:

Almost NVME Drives are designed to run with CHIPSET LANES and i have to disagree if its gonna be at sata speed cause X4 has 10Gbps transfer while sata 3 is 6Gbps bandwidth.

And no your M.2 slot will not run in sata speed.

In theory but in practice u wont be able to see the difference in real world scenarios unless u benchmark it but NVME are superior for transfering large sized data at once.

Here's the specs quoted from the manufacturer

  Hide contents

1 x PCI Express x16 slot, running at x16 (PCIEX16)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.

 

 

1 x PCI Express x16 slot, running at x8 (PCIEX8)
* The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.

 

1 x PCI Express x16 slot, running at x4 (PCIEX4)
* The PCIEX4 slot shares bandwidth with all PCI Express x1 slots. All PCI Express x1 slots will become unavailable when a PCIe x4 expansion card is installed.

As u can see u can SLI 970 and still running the NVME drives at Pcie x4 speed

well if you run pcie 4x its running to the cpu and not the southbridge. 10Gbps transfer are for the sata express and it uses 2 pcie lanes. "PCI Express 3.0's 8 GT/s bit rate effectively delivers 985 MB/s per lane, practically doubling the lane bandwidth relative to PCI Express 2.0." so 985*4=3940 MB/s. and everything running to the southbridge will get sata3 speed that is 550MB/s - 600MB/s. i really want you to take a look at your lanes to make sure that one of your gpus are not running at 4x since the cpu only can support up to 16x total also i want you to test your pcie ssd speed to make sure that its not running over sata3 or sataExpress. source

- http://www.samsung.com/semiconductor/minisite/ssd/product/consumer/ssd960.html

- https://en.wikipedia.org/wiki/PCI_Express

[Hiya!]

19 minutes ago, Xino said:

well if you run pcie 4x its running to the cpu and not the southbridge.

Why?

 

19 minutes ago, Xino said:

and everything running to the southbridge will get sata3 speed that is 550MB/s - 600MB/s

How?

[Xino]

2 minutes ago, Hiya! said:

Why?

 

How?

because you have total of 16x lanes, and you are calculating in binary so if you so if you have 1 gpu only it can run with 16x if it supports it if you run sli you have to divide that with 2 so 16/2=8 that means that you have 2 gpus running 8x each so if you connect a pcie device fx. pcie ssd that takes 4x lanes then it take 1x of your 8x for the gpu and divide that with 2 again so 8/2=4 so now you have a total of 8x for 1 gpu, 4x for second gpu and 4x for the pcie ssd. meaning 8+4+4=16 lanes.

[Princess Luna]

2 minutes ago, Xino said:

8x for 1 gpu, 4x for second gpu

It does not work this way, SLI will only work if it is both cards are on x8 x8.

 

SLI is not worth it sell the 970 you have and get something better, 980 Ti , 1070 Ti... call it a day.

[Hiya!]

1 minute ago, Xino said:

because you have total of 16x lanes, and you are calculating in binary so if you so if you have 1 gpu only it can run with 16x if it supports it if you run sli you have to divide that with 2 so 16/2=8 that means that you have 2 gpus running 8x each so if you connect a pcie device fx. pcie ssd that takes 4x lanes then it take 1x of your 8x for the gpu and divide that with 2 again so 8/2=4 so now you have a total of 8x for 1 gpu, 4x for second gpu and 4x for the pcie ssd. meaning 8+4+4=16 lanes.

uhm no sli will work only if both gpu are using x8.

but afaik most consumer nvme are designed to run over chipset lanes and u said everything that use southbridge lanes will have the speed of sata3 i still didnt understand  why? why southbridge is much more slower? did u have an article for that?

[Xino]

10 minutes ago, Hiya! said:

uhm no sli will work only if both gpu are using x8.

but afaik most consumer nvme are designed to run over chipset lanes and u said everything that use southbridge lanes will have the speed of sata3 i still didnt understand  why? why southbridge is much more slower? did u have an article for that?

then your ssd are running sata

[Xino]

12 minutes ago, Princess Cadence said:

It does not work this way, SLI will only work if it is both cards are on x8 x8.

 

SLI is not worth it sell the 970 you have and get something better, 980 Ti , 1070 Ti... call it a day.

i got an gtx 1080 no problem

[pas008]

z97 has 8 chipset lanes but is tied to dmi which usually runs at 4x speed

but to saturate all your devices on chipset must be pushing that 4x bandwidth at same time I believe

 

1080ti sli with 650ti here 2x m.2 and 4x ssd/hdd on z370 mobo

 

1080ti sli on cpu lanes, rest on chipset lanes,

now I suppose it I'm trying to pull bandwidth from all my m.2 and ssds I might get a bottleneck but they must be pretty big files all at once

 

[Glenwing]

Ok.

 

LGA 1150 CPUs provide 16 PCIe 3.0 lanes (≈1 GB/s per lane). These are called the primary PCIe lanes. Most full-length PCIe slots are connected to these lanes. If you connect multiple devices to PCIe slots which are connected to primary lanes, only 16 total lanes are available to split between all those devices.

 

In addition to the 16 PCIe 3.0 primary lanes provided by the CPU, there are another 8 PCIe 2.0 lanes (500 GB/s per lane) provided by the motherboard chipset, called the auxiliary PCIe lanes. These are generally used by the motherboard manufacturer for add-on features such as additional USB 3.0 ports (chipset provides only 6), network controllers, M.2 slots, all of the PCIe x1 slots, etc. Sometimes if the motherboard has a third full-length slot at the bottom wired only for x4, it will actually be connected via auxiliary lanes (being a PCIe 2.0 slot is the giveaway).

 

Whether a device uses primary or auxiliary lanes depends on which slot it is connected to. Devices do not "choose" which lanes to use based on what type of device they are. It is up to the board manufacturer to connect the slots intelligently based on what they think people will use them for. If an M.2 slot is "10 Gbit/s" then it is using PCIe 2.0 and you know it is connected via auxiliary lanes (this is specific to platforms like Z97 where the chipset lanes are 2.0).

 

Although the chipset provides 8 PCIe 2.0 lanes, it is connected to the CPU through something called the DMI 2.0 bus, which is equivalent to PCIe 2.0 x4 speed (≈2 GB/s. All of the I/O from the chipset combined cannot exceed this speed including all SATA ports, USB ports, network ports, and M.2 slots. This is generally enough not to be a problem (i.e. it will not reduce M.2 drives to SATA speeds usually), it is expected people will not try to saturate every I/O port at the same time, and this assumption is usually correct.

 

So yes, you can run two GPUs at x8/x8 and use an M.2 SSD at the same time.