Will GPU performance affected while in x8 pci-e lane?

[chanwei21]

Hi guys,

Because of CPU lane counts.
Will the graphic card unit performance effected running at x8 PCI-E done by some lacking CPU lane?

example running a 7700k which is 16 pcie lane CPU and running a GPU in x8 PCI-E and 2pcs of NVME M.2 SSD which eats x4+x4 PCI-E lane?

 

[rgd1101]

ssd use lane from the chipset not from the cpu
http://www.tomshardware.com/news/intel-200-series-chipsets,33305.html

and x8 is fine for gpu

 

[SkyNetRising]

ssd use lane from the chipset not from the cpu

Not always. It's possible to use PCIE M.2 add-in card and tap into cpu pcie lanes also.

 

[geofelt]

For graphics, there is miniscule difference.

Running a GTX1080 on X16 vs. X8 results on at most a 1% difference in average or minimum fps.

 

[turbopixel]

geofelt, its true
> https://linustechtips.com/main/topic/608355-gtx-1080-pcie-30-x8-bottleneck/
> https://www.youtube.com/watch?v=XJuj16gRoBI

 

[rgd1101]

ssd use lane from the chipset not from the cpu

Not always. It's possible to use PCIE M.2 add-in card and tap into cpu pcie lanes also.

does it? Where did you see one?

 

[SkyNetRising]

does it? Where did you see one?

There are plenty of such adapters.

 

[rgd1101]

does it? Where did you see one?

There are plenty of such adapters.

I see plenty of adapter, but didn't see it using cpu lane.

I only know of desktop cpu offer m.2 lane is AMD ryzen, the rest are using chipset lane.

 

[SkyNetRising]

If the adapter is placed in PCIE x16 slot for graphics card (that uses cpu pcie lanes), then obviously it will use cpu pcie lanes.

 

[rgd1101]

If the adapter is placed in PCIE x16 slot for graphics card (that uses cpu pcie lanes), then obviously it will use cpu pcie lanes.

oh. NO. I don't think that how it work

http://www.tomshardware.com/news/intel-200-series-chipsets,33305.html
as far as I know, the cpu is smart enough to know if expansion card is a graphic or not

 

[SkyNetRising]

How did you think it works then?
Did you think pcie lanes (in same pcie slot) get rerouted from cpu to chipset depending on what type of card is used?

 

[rgd1101]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

 

[SkyNetRising]

That is not data routing. Those are hardwired electrical connections.
Currently I'm not aware of such tech, that would allow switching between cpu lanes and chipset lanes within same pcie slot.

 

[rgd1101]

That is not data routing. Those are hardwired electrical connections.
Currently I'm not aware of such tech, that would allow switching between cpu lanes and chipset lanes within same pcie slot.

how do bios know which ram, gpu, hdd/sdd you install? That you have a gpu, and not a sound card in the slot so don't use the igpu?

 

[RobCrezz]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

 

[rgd1101]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

So, since the cpu only do graphic lane, if were to put in a sound card on that slot, it will not works?

 

[RobCrezz]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

So, since the cpu only do graphic lane, if were to put in a sound card on that slot, it will not works?

What? PCI-E isnt just for graphics, its for any add in card. Are you trolling?

 

[rgd1101]

Lane on Intel cpu is call PCI Express Graphics Interface (PEG)
read it on intel site
https://www.intel.com/content/www/us/en/processors/core/7th-gen-core-family-desktop-s-processor-lines-datasheet-vol-1.html
also on the chipset chart
http://www.tomshardware.com/news/intel-200-series-chipsets,33305.html

Although it does look like you can use it for other think if you using the iGPU
https://electronics.stackexchange.com/questions/216451/difference-between-general-purpose-pcie-signals-and-pci-express-graphics-peg

 

[rgd1101]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

So, since the cpu only do graphic lane, if were to put in a sound card on that slot, it will not works?

What? PCI-E isnt just for graphics, its for any add in card. Are you trolling?

We are talking about pcie lane not pcie slot.

 

[RobCrezz]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

So, since the cpu only do graphic lane, if were to put in a sound card on that slot, it will not works?

What? PCI-E isnt just for graphics, its for any add in card. Are you trolling?

We are talking about pcie lane not pcie slot.

So am I. PCI-E lanes are not just for graphics cards, they can be used for all kinds of devices (sound cards, HBAs, network cards etc etc.).

 

[rgd1101]

You don't think the cpu is smart enough to know how to route data? know what is plug in? that cpu don't communicate with the chipset?

Some slots will be wired to the CPUs pci-e lanes, some to the PCH (usually the x1 slots).

m.2 is usually wired to the PCH.

So, since the cpu only do graphic lane, if were to put in a sound card on that slot, it will not works?

What? PCI-E isnt just for graphics, its for any add in card. Are you trolling?

We are talking about pcie lane not pcie slot.

So am I. PCI-E lanes are not just for graphics cards, they can be used for all kinds of devices (sound cards, HBAs, network cards etc etc.).

read my other post about PEG

They can use for all kinds of devices, yes, but still have to follow intel chipset spec, some are for USB, SATA only
same thing, read the post about PEG