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Question How to check if everything is running PCIe 4.0 or 3.0 ?

ohm-ish

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Jan 11, 2016
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Just got my new build running
Asus Z790-I motherboard
i5-13600k CPU
WD Black 2 TB NVME
RTX 4070 GFX
2 x 16 GB DDR5 RAM

How can I check if my system or some parts is using PCIe 4.0 or 3.0? And something about lanes..
Maybe the gfx card is at 3.0 and that would be "ok". But for other parts I want the fastest possible
I just want to see and make sure what version/speed everything is
And so that everything is running at fastest possible bandwidth
 
Just got my new build running
Asus Z790-I motherboard
i5-13600k CPU
WD Black 2 TB NVME
RTX 4070 GFX
2 x 16 GB DDR5 RAM

How can I check if my system or some parts is using PCIE 4.0 or 3.0? And something about lanes..
Maybe the gfx card is at 3.0 and that would be "ok". But for other parts I want the fastest possible
I just want to see and make sure what version/speed everything is
And so that everything is running at fastest possible bandwidth
Check your motherboard manual
 
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Just got my new build running
Asus Z790-I motherboard
i5-13600k CPU
WD Black 2 TB NVME
RTX 4070 GFX
2 x 16 GB DDR5 RAM

How can I check if my system or some parts is using PCIE 4.0 or 3.0? And something about lanes..
Maybe the gfx card is at 3.0 and that would be "ok". But for other parts I want the fastest possible
I just want to see and make sure what version/speed everything is
And so that everything is running at fastest possible bandwidth
Your processor has 20 lanes that will run a m.2 4.0 drive (that runs off the CPU lanes) and a 4.0 X16 video card.

You never listed the exact drive so it could be 3.0 or 4.0
 
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So I checked in cpu-z and got this.
It all seems to be PCIE 4.0
Now I just wonder about the current vs maximum link speed at the graphic interface (bottom)
But I guess it's alright?

LJncit2.jpg
 
Graphics card is currently running in PCIE 1.1 x8 mode.
Probably because of power saving.

Click on "?" - next to Bus interface text box and start render test.
Bus interface should change to PCIE 4.0 x16.
Ah ok, and so I watch if the PCIE version switches to higher during the test window?
I could assume it's running on low bandwidth while in desktop idle mode
 
Looks like your system might be set to PCIe 5.0 for the NVMe which is halving your lanes to your GPU. So while it's running PCIe 4.0 it is only getting half of the lanes. If you have the option of putting the NVMe slot into PCIe 4.0 mode this should fix that. Intel platforms with PCIe 5.0 NVMe support pull from the CPU lanes (dumb design, but mobo makers gotta check that box) which is the issue there.

Ah ok, and so I watch if the PCIE version switches to higher during the test window?
I could assume it's running on low bandwidth while in desktop idle mode
That is exactly what it is supposed to be doing and as long as it changes you're good.
 
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Looks like your system might be set to PCIe 5.0 for the NVMe which is halving your lanes to your GPU. So while it's running PCIe 4.0 it is only getting half of the lanes. If you have the option of putting the NVMe slot into PCIe 4.0 mode this should fix that.

Ok thanks.
Is there a recommended tool like cpu-z but for drives, like an nvme-z? 😉
Or do you know how to set my nvme to run at pcie 4.0 only?
 
Ok thanks.
Is there a recommended tool like cpu-z but for drives, like an nvme-z? 😉
Or do you know how to set my nvme to run at pcie 4.0 only?
From the manual:
* M.2_1 comes from Intel® Z790 Chipset when PCIe Gen5 expansion slot is switched to x16 mode. This can be configured in the BIOS under the Advanced > Onboard Devices Configuration menu.

As for SSD checking it was already mentioned above: https://forums.tomshardware.com/thr...running-pcie-4-0-or-3-0.3823098/post-23115733
 
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Ah I see
btw my graphics card went to say PCIe x16 4.0 @ x8 4.0 in gpu-z when I did the render test
Maybe that's fine for a gfx card?
I'm not sure if it would even utilize a higher bandwidth.
But maybe it's best if everything is in pcie 4.0 at highest if it can
So I will look into setting the NVMe to 4.0 in bios
 
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Ah I see
btw my graphics card went to say PCIe x16 4.0 @ x8 4.0 in gpu-z when I did the render test
Maybe that's fine for a gfx card?
I'm not sure if it would even utilize a higher bandwidth.
But maybe it's best if everything is in pcie 4.0 at highest if it can
So I will look into setting the NVMe to 4.0 in bios
You lose absolutely nothing by forcing the slot to x16 and SSD over to the chipset. It would only make any difference if you were running a PCIe 5.0 SSD.
 
You will need to physically move the drive from the CPU connected M.2 slot to the chipset connected M.2 slot, not a BIOS setting.
Hm ok that's something I really want to avoid 😉
I read that "PCIe 4.0 x8 is close to equivalent bandwidth to PCIe 3.0 x16"
So that would be fine for me.. 2-3-4 fps doesn't matter much
 
You may be right. That board is expensive enough to justify putting a PCIe switch chip in there. So according to the manual you can force the GPU to x16 mode which will run the "Hyper" M.2 through the chipset.

So weirdly the board has three logical M.2 slots, but only two physical. MIni-ITX for you.
 
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Ok. I wonder why the GPU is in x8.
As I recall the bios is set to auto pcie mode, so it should use x16?
Because you have not forced M.2 slot into gen4 mode.

In gen5 mode (or auto) M.2 slot is using PCIE lanes from CPU
(and just downgrades PCIE mode internally to gen4 because of gen4 drive)
Gpu slot has to be switched from x16 to x8, to accommodate that.

In forced gen4 mode M.2 slot is using PCIE lanes from chipset and gpu is free to use all x16 connectivity from available CPU PCIE lanes.
 
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