Spinrite 6.0 on Virtualbox (Linux)

I have found a significant difference in performance depending how the VM is configured in VirtualBox (IDE vs SATA). This is the process I follow to scan hard disks connected via USB adaptors on a Virtual Machine:

Create the VM

1. Type: Other, Version: DOS
2. System: Disable Floppy; Memory: 128MB
3. Storage
   1. Remove the IDE Storage Controller
   2. Add a SATA Controller, enable Host I/O Cache
   3. Add an Optical Drive and choose the Spinrite.iso
   4. Insert the USB drive
   5. As root type dmesg on the command line and identify the device, for example /dev/sdb
   6. chmod o+rw /dev/sdb
   7. As the user running VirtualBox run:
      VBoxManage internalcommands createrawvmdk -filename VirtualBox/sdb.vmdk -rawdisk /dev/sdb
   8. Add a Hard Disk to the SATA Controller > existing disk: sdb.vmdk
4. Sound: Disabled.
5. Network: Disable the Network adapter.

Using the default IDE storage controller slows down the scan by a factor of 10 (approx)

The lack of support for GPT partition tables of the current version of Spinrite (6.0) is a major drawback. I still use it for checking hard disks and data recovery with my old drives, or with new ones, as long as I initiate them with a MBR partition table.