PCIE Lane Sharing Questions

Hardware & Gaming Graphics Cards & GPUs
1

Is PCIE lane sharing that bad these days esp with PCIE Gen 5? As even a RTX 5090 does not fully saturate a PCIE 5 x8 slot, what is the big deal if the gpu runs at PCIE 5 x8 or PCIE 4 x8 (eg. in case of 4000 series cards) speeds? esp. mid tier GPUs?

Have any of you had problems with lane sharing in modern motherboards esp. X870E B850 etc?

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Unless you use a DIMM.M2 slot, you can’t use the full x16 lanes on your GPU, with more than one NVMe, in most cases.

I have an X870 Aorus Elite. I have 3 NVMEs running, only the top slot is directly connected to the CPU, the moment you populate the 2nd one, your GPU lane will drop to x8

Won’t really matter, though:

My 3080 is currently running at PCIe 4.0x8, which is essentially PCIe 3.0x16. Zero performance difference. Hell, even the RTX 5090 shows barely a 4% difference between Gen 3 and 5

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Yeah saw the GN video and it is one of the reasons for starting the thread.

Btw this guy visually breaks down the lane sharing in recent AMD motherboards:

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