Bringing this old thread from the grave, but it did resolve my issue 5 years laters, on an overclocked i7- 8700K and very LOW CPU AES.
The tests would result in 21000MB/s, with Intel Virtualization Technology enabled. Once that was disabled in BIOS, test results jumped 33000MB/s.
Thank you!
MB - Asrock Z370 Gaming K6 (3.20)