Process Monitor : Help on IRP_MJ_READ Process Name!

https://www.wetransfer.com/downloads/1e02b92fb55cebd70e92b0a164fe1a0620141108113520/addb1b

This explains it very well indeed, you will see as the problem runs it all of a sudden simply stops using FASTIO and the System takes over the file handling, no users on the system apart from me. This is a mid flow performance change during file reading.

The first run used just IRP for XRTEClient, second runs started with FASTIO on XRTEClient then switched to IRP and System.

All calls after this have gone back to FASTIO now, flushing the list goes back to IRP for first run and all now are FASTIO. At some point it will simply switch off using FASTIO and go back to using IRP even although the read milliseconds before hand read the same file block :(. Very odd behaviour considering the file size is so small.