Quite the opposite is true. If you are using the PCIe bus a lot you probably aren't making good use of the GPU.
A GPU has it's own processor and RAM. If you're transferring to your system RAM and back again often enough to max out x16 PCIe lanes you should fix that.
A GPU has it's own processor and RAM. If you're transferring to your system RAM and back again often enough to max out x16 PCIe lanes you should fix that.