That's definitely something that should be taken into account, especially on newer "consumer" CPUs which may actually not even have enough lanes for a GPU and NVMe drive [0].
In my case, the CPU has 40 PCIe lanes, and all PCIe 16x slots on the motherboard are electrically 16x.
In my case, the CPU has 40 PCIe lanes, and all PCIe 16x slots on the motherboard are electrically 16x.
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[0] For example, the i5-8500 only has 16 lanes total: https://ark.intel.com/content/www/fr/fr/ark/products/129939/...