PCIe 2.0 x 4 > 2.000 GB/s
PCIe 3.0 x 2 > 1.969 GB/s
But we also have to consider the suggested ARM CPU does PCIe 2.1 and we’ve to add the this detail:
PCIe 2.1 provides higher performance than the PCIe 2.0 by facilitating a transparent upgrade from a 32-bit data path to a 64-bit data path at 33MHZ and 66MHz.
I shouldn’t also have a large impact but maybe we should think about it a bit more.
Anyways I do believe this really depends on your use case, if you plan to bifurcate it or not and what devices you’re going to have on the other end. For instance for a NAS I would prefer the PCIe 2.1 x 4 as you could have more SATA controllers with their own lanes instead of sharing lanes in PCIe 3.0 using a MUX.
Conclusion: your mileage may vary depending on use case. But I was expecting to have more PCI lanes exposed be it via more m.2 slots or other solution. I guess that when a CPU comes with everything baked in and the board maker “only has” to run wires around better do it properly and expose everything. Why not all SATAs for instance?
Generally, there’s a small difference in speeds:
But we also have to consider the suggested ARM CPU does PCIe 2.1 and we’ve to add the this detail:
I shouldn’t also have a large impact but maybe we should think about it a bit more.
Anyways I do believe this really depends on your use case, if you plan to bifurcate it or not and what devices you’re going to have on the other end. For instance for a NAS I would prefer the PCIe 2.1 x 4 as you could have more SATA controllers with their own lanes instead of sharing lanes in PCIe 3.0 using a MUX.
Conclusion: your mileage may vary depending on use case. But I was expecting to have more PCI lanes exposed be it via more m.2 slots or other solution. I guess that when a CPU comes with everything baked in and the board maker “only has” to run wires around better do it properly and expose everything. Why not all SATAs for instance?