RX7900 XTX always show PCIe x16 4.0

[aiccqtc]

When the system is idle, there is no load on the graphics card,
But the Bus interface always show PCIe x16 4.0 , Why isn't down to PCIe x16 1.1
(Try Nvidia Graphics cards it works normal)

 

[GerKNG]

RDNA3 does that. my 7800XT is always at x16 4.0

 

[AusWolf]

RDNA3 does that. my 7800XT is always at x16 4.0

Really? Mine goes all the way down to PCI-e x1 1.1.

When the system is idle, there is no load on the graphics card,
But the Bus interface always show PCIe x16 4.0 , Why isn't down to PCIe x16 1.1
(Try Nvidia Graphics cards it works normal)

What is your monitor config?
What background apps do you have running? Even ones that are minimised to the tray can put a load on the GPU sometimes.
What is your PCI-e power saving setting in Windows?

 

[GerKNG]

Really? Mine goes all the way down to PCI-e x1 1.1.

with high resolution, high refreshrate displays?

 

[Macro Device]

Also having exact the same behaviour. Will check my 1080p display if that will change things.

Now that's weird.

AMD definitely have something went horribly wrong in their drivers.

 

[Todestrieb]

This thread prompted me to check what my current card (3070) is running at after sticking a 4K high refresh monitor. It is PCIe x16 3.0. (My board can't go PCIe 4.0).
I'm pretty sure without the 4K monitor it should be PCIe 1.1.

 

[AusWolf]

with high resolution, high refreshrate displays?

I've got two displays connected, one is 3440x1440, 144 Hz and the other is 1024x600, 43 Hz.

 

[Vya Domus]

My 7900XT stays at PCIe x16 4.0 all the time as well, probably has to do with what kind of monitors are attached. Why does this bother you anyway ?

 

[R-T-B]

This may have a lot to do with your windows power plan and bios ASPM settings as well.

It won't downrate if ASPM is disabled by either.

 

[iameatingjam]

Is it power you are concerned about?

 

[R-T-B]

Why does this bother you anyway ?

Is it power you are concerned about?

It's not working as intended so yeah people are going to be concerned about unwanted power usage. The amount is pretty irrelevant (we all know it's not a ton), it's more of a bug report I picture. It'd hurt mobile devices the most.

 

[lowrider_05]

If you touch the Overclocking Panel in the Radeon Settings, it will also stay on full PCIe bandwidth.

 

[iameatingjam]

Well I just did a little experiment and found out you can change it here, for nvidia at least:

 

[Vya Domus]

It's not working as intended

It is working as intended, this is just a power saving feature, if the PCIe connection doesn't slow down it's because something that's running on the GPU is preventing it from doing that. It be a problem if it was the other way around.

 

[R-T-B]

It is working as intended, this is just a power saving feature, if the PCIe connection doesn't slow down it's because something is preventing it from doing that.

Well, it might be that as well as I mentioned (disabled in BIOS or similar). But if that's not the case it could be a driver bug of some kind. We really need more data to say right now, true.

It also could be architectural: maybe the chiplet design uses the PCIe bus for some small function, and keeps it busy.

 

[aiccqtc]

My 7900XT stays at PCIe x16 4.0 all the time as well, probably has to do with what kind of monitors are attached. Why does this bother you anyway ?

Just a little doubt.
Verification with RX580 , It will down to PCIe x16 1.1 , but it's not the same driver.
It may be related to the driver

 

[AusWolf]

It also could be architectural: maybe the chiplet design uses the PCIe bus for some small function, and keeps it busy.

It's not. My 7800 XT scales all the way down to PCI-e x1 1.1.

Well I just did a little experiment and found out you can change it here, for nvidia at least:

This is the most likely culprit, imo.

 

[Chrispy_]

My 7900XT stays at PCIe x16 4.0 all the time as well, probably has to do with what kind of monitors are attached. Why does this bother you anyway ?

I'm also wondering what the issue is. Your flagship, power-hungry card is running the PCIe slot at the speed it's advertised to run at. I'm assuming you haven't put the PC in Windows' "Max performance" mode which disables most energy saving features.

Honestly, the slot speed/width is dependent more on the motherboard and BIOS settings than the GPU, so the fact it's not scaling back lanes likely means you have some of the power management options in the BIOS disabled.

It's a moot point - the 1-2W of power saving from enabling those features is lost in the noise of a desktop PC's power consumption, even at idle. If you really want to change it, there's nothing in the driver or on the graphics card that you can change, dive into your BIOS and hunt for PCIe power management options. It's a waste of effort in my opinion, but feel free to tinker if it makes you feel better.

 

[iameatingjam]

When the system is idle, there is no load on the graphics card,
But the Bus interface always show PCIe x16 4.0 , Why isn't down to PCIe x16 1.1
(Try Nvidia Graphics cards it works normal)

View attachment 320530

Just incase you missed it, as others seem to have, search 'choose a power plan' in your start search bar. Whatever plan you are on, click change plan settings, then 'change advanced power settings,' then scroll down to 'PCI express', then 'link state power management' and choose moderate or maximum power savings.

It is working as intended, this is just a power saving feature, if the PCIe connection doesn't slow down it's because something that's running on the GPU is preventing it from doing that. It be a problem if it was the other way around.

Agreed, as somebody who has once been on the opposite end of this, the number being low is the problem not the other way around.

 

[Macro Device]

scroll down to 'PCI express', then 'link state power management' and choose moderate or maximum power savings.

Doesn't change anything in my case.

 

[iameatingjam]

Doesn't change anything in my case.

Interesting. It worked for me. Maybe it is an nvidia vs amd thing. Or maybe something needs the bandwidth like multiple displays? Idk.

 

[Macro Device]

maybe something needs the bandwidth like multiple displays?

Nah, it's a single 1080p75 display. Can't be too much for 1.1.

Most likely a driver issue.

 

[Chrispy_]

Interesting. It worked for me. Maybe it is an nvidia vs amd thing. Or maybe something needs the bandwidth like multiple displays? Idk.

It's a BIOS thing. The windows settings do nothing if the BIOS doesn't have it set to AUTO.

 

[Macro Device]

It's a BIOS thing. The windows settings do nothing if the BIOS doesn't have it set to AUTO.

But how do you explain the fact one GPU behaves normal (goes PCI-e 1.1 on idle) and another always stays PCI-e 4.0

 

[Chrispy_]

But how do you explain the fact one GPU behaves normal (goes PCI-e 1.1 on idle) and another always stays PCI-e 4.0

They're different GPUs, made 7 years apart. Expecting them to behave identically is illogical.

You'd need an AMD rep to get you a definite answer but it's possible newer GPUs don't do it because the power savings are negligible and the risks of issues with BIOS/Windows not handling energy management 100% correctly is not something AMD want to be deal with? I know for a fact those have been problematic for multi-GPU systems from both AMD and Nvidia in the past two decades. Like SLI, culling PCIe lanes to save power may just be deprecated on desktop GPUs now.

For the record, even with PCIe link state power management enabled in the BIOS, and with the W11 power plan on balanced, my 4060Ti is sat at PCIe 4.0 x8 as expected. It also does not drop down to PCIe 1.1.