If you want performance, you still better do it through DMA transfers that bypass the CPU, because otherwise, the CPU will still be waiting for thousands of cycles to fetch data from the device on the other side of the bus.
And the transfers that are done by the CPU should be write-only to the bus as much as possible.
PCIe 3: 16 lanes * 8 Gtransfers/s * 128/130 (encoding) : ~126 Gbit/s
So, yes, it has changed quite a bit!
But so has everything else.
If you want performance, you still better do it through DMA transfers that bypass the CPU, because otherwise, the CPU will still be waiting for thousands of cycles to fetch data from the device on the other side of the bus.
And the transfers that are done by the CPU should be write-only to the bus as much as possible.