Question Just bought a RX 7800XT and at current bus it says it runs on PCI EXPRESS 3.0

[fasadasa]

Hello, so I have the following question, my motherboard is an ASUS PRIME B550M-A and in AMD software it says that it runs on PCI EXPRESS 3.0 and I am confused if i am supposed to do something for it to work on PCI EXPRESS 4.0 or maybe my motherboard does not support this?

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[USAFRet]

Hello, so I have the following question, my motherboard is an ASUS PRIME B550M-A and in AMD software it says that it runs on PCI EXPRESS 3.0 and I am confused if i am supposed to do something for it to work on PCI EXPRESS 4.0 or maybe my motherboard does not support this?

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What CPU do you have?

 

[copilu]

Hello, If you have an ATX motherboard, try moving the GPU to the top PCI-E. If not, check CPU support and if none of the first and second is the problem, then try enabling pci-e 4.0 in BIOS (

View: https://www.youtube.com/watch?v=nVHDuudRqpM
)

 

[fasadasa]

What CPU do you have?

r7 5700

Hello, If you have an ATX motherboard, try moving the GPU to the top PCI-E. If not, check CPU support and if none of the first and second is the problem, then try enabling pci-e 4.0 in BIOS (

View: https://www.youtube.com/watch?v=nVHDuudRqpM
)

My motherboard is not atx, i have only one slot i will try enabling it from bios

 

[beyondlogic]

r7 5700

My motherboard is not atx, i have only one slot i will try enabling it from bios

Your cpu isn't a true 5000 series it has PCI gen 3 lanes.

It's quite confusing but not all 5000 are equal.

E.g 5700x has PCI gen 4 code name Vermeer

5700 is limited to PCI gen 3 code name Cezanne

 

[fasadasa]

Your cpu isn't a true 5000 series it has PCI gen 3 lanes.

It's quite confusing but not all 5000 are equal.

E.g 5700x has PCI gen 4
5700 is limited to PCI gen 3

oh, so basically the only way to be able to have pci express 4.0 is to buy a new cpu?

 

[beyondlogic]

oh, so basically the only way to be able to have pci express 4.0 is to buy a new cpu?

Correct.
PCI gen 4 CPUs below

R7 5700x
R7 5700x3d
R9 5900x

 

[artk2219]

Youre not really missing out on anything by running it on PCIE 3.0 X16, maybe 2 - 3% performance on the top end, basically its margin of error, and that was with an RTX 4090. I imagine you would see even less of a loss with an RX 7800 XT.

https://www.techpowerup.com/review/nvidia-geforce-rtx-4090-pci-express-scaling/28.html

https://www.techpowerup.com/review/nvidia-geforce-rtx-3080-pci-express-scaling/27.html

 

[beyondlogic]

While you won't see much benefit from moving from a new cpu from 3.0 to 4.0 on x16 lanes.

Different story if say the GPU was cut to 4x8 lanes on 3.0 bus.

But because your GPU is wired x16 not 8 that won't be a issue. Like 3-5 percent. Might become a issue with game later that get bandwidth hungry.

There is 1 glaring thing to keep in mind that because cpu is running 3.0 lanes your top nvme slot will be restricted to 3.0 X4 speeds.