Thankyou so much for your help. Also may I ask how did you know Whiskey Lake-U supports only x2 PCIe 3.0 for its SSD M.2 socket. Are there sources that I can know more regarding this type of information?Your OS will cache writes in RAM but if you're going at a steady pace the bottleneck is the drive ultimately. Likewise, certain transfers do have I/O overhead (esp. many small files), but generally speaking the limit will be the drive and not the CPU's overhead. Exception would be with compression of course which is RAM- and CPU-heavy, backup software generally does use moderate compression.