You are already running the Intel AHCI driver ver. 126.96.36.1996 and not the native windows OS AHCI driver. That's the reason why you do not have storahci.sys which is the OS's native AHCI driver. It either has been installed through WU or manually via Intel RST. It's been reported that Intel RST version 15 causes issues. I am not sure if it has been fixed at the 17.x versions. I firstly would either uninstall Intel RST OR to rollback to the native AHCI driver coming from the OS (default). The native AHCI drivers are old, but actually are running well. Only drawback (on very old systems) can be that SSDs are listed as removable drives. (On my old PC for instance). There are lots of discussions if installing Intel RST makes sense at all or to use the native MSFT driver. Many people say that if one does not use any RAID it makes not much sense. Additionally some people say that the native MSFT AHCI driver is used by SSD's vendors to optimize their SSD firmware. It makes sense to optimize for OS default drivers rather than to optimize for Intel's own (except you are running a SSD from Intel of course). After you have rolled back to native MSFT AHCI I would repeat the tests. The native AHCI driver's name is storahci.sys. Recheck that first. If it should not resolve the issue you can try what I have posted afterwards (reg edit) since you now are running storahci.sys. The regedit BTW I have found on several other sites, but I never have tried it myself since I do not have issues using storeahci.sys. I hope it works out for you. Another thing that I firstly thought about is all the meltdown / spectre patching which is from the technical aspect a total mess since it is totally made without any concept. Some have updated microcodes in combination with other patches and the latest w10 has retpoline included. (which also caused performance issues at special situations). Also 1809 should have got retpoline update already...I even don't know if it's active there... Who knows if it slows down file copy operations if a special patch situation would turn out very negative?