Why does disk to disk activity on unrelated drives (d:\,e:\) lag system (via c:\) Win10

Question

If im copying large files from nonOS D: to nonOS E:

and Paging is on C:

IO will be slowed on C:, as noted by longer loading times, browser cache lag, etc...

(end question)

Optional Q: Is there a solution?

Answer 1

This is a correct observation. Dispite being on different drives, the transfer is still (likely) handled by the same SATA controller and is still being processed by the CPU. Along with that, Windows is still doing some processing of the files (things like permission calculations, virus scans, etc).

There could be some ways to improve this, a little at least. Some motherboards have multiple SATA controllers to split the load (it isn't dynamic, it is based on which controller the drive is connected to), this could cause the same issues if your OS disk is on the same controller, or it could improve some things is say one controller is reading, sending the data to the North Bridge (I believe it's North in this case) and then to the other controller where the writing would be handled, instead of read and write on the same one, but I'm not 100% on that.

It would also be faster if it were on the same disk, as the MBR would just update the pointers to the data.

Edit: you may also see some improvement in using the windows command line and the robocopy command. This is a little less load, and depending on what you're doing, you could use some flags to reduce calculations needed (permissions, error checking, etc)