VMWare Workstation SCSI vs SATA Performance

During the many years that I have used VMWare Workstation, I have noticed that there are periodically times where the disk momentarily stops responding and the virtual machines lock up. After the disk has churned for some time, the guest becomes responsive. This may happen several times throughout the day.

I am running a PC with the following specs:

• CPU - Intel Core I7 - 3rd Generation
• RAM - 32 GB
• OS Disk - 256 SATA SSD
• Virtual Machine Disk - 512 SATA SSD
• Operating System - Windows 10
• Hypervisor - VMWare Workstation 12

Today, I decided to try changing out my SCSI virtual disks to SATA virtual disks. I manually modified the .VMX files with the necessary changes.  Much to my surprise, the disk performance increased.

I was previously using the LSI SCSI controller for my virtual disks. But, the periodic freeze behavior was occurring quite often. It was getting so bad that I decided to search the Internet for a solution. My attempt at switching to SATA was a blind stab in the dark.

Having switched to my virtual disks to use the SATA controller, instead of the LSI SCSI controller, I haven't seen as much freezing - almost none. For whatever reason, the higher performing controller was causing my virtual machines to lock up for seconds at a time. The result is that I am achieving far better performance with the SATA controller.