M.2 to pci adapter is it better than pci 4 x2 the bandwidth speed of pci 4 x2 is 8GB/s

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but what is the speed of the m.2 will it be better if i plug my gbu of pci 4 x8 on it with adapter or pci 4 x2 better

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M.2 from the Motherboard chipset is 4 x4

M.2 to pci 4 Better but can it handles the gpu load