For TRIM feature to work, both the host Operating System and the devices must support the feature, and it must be enabled in both sides.
TRIM feature in Pegasus2 M4:
Promise’s Pegasus2 M4 is recognized as Serial Attached SCSI (SAS) device by Operating System regardless of what type of SSD is being used. With the latest FW version 5.04.0000.57, Pegasus2 M4 support TRIM feature is enabled by default. Users can manually disable the TRIM feature support in Pegasus2 M4 by command line: ctrl –a mod –s “trim=disable, but it is not recommended.
TRIM feature in Mac Operating System:
Current OS X (even the latest 10.11.x) ONLY supports TRIM feature for SSD in AHCI mode of SATA (Serial ATA) device, but not support for SAS device. Since Promise’s Pegasus2 M4 is recognized as SAS (Serial Attached SCSI) device under Mac Operating System. Therefore, the TRIM command will not be sent to Pegasus M4 SSD.
Mac OS X 10.12 may support TRIM feature for SAS device. We will update this document after next OS X version release.
TRIM feature in Windows Operating System:
In Windows 7, the situation is same as current Mac OS X situation.
Pegasus2 M4 SSD does not get benefit of TRIM feature because Windows 7 only support TRIM feature for SATA devices. TRIM feature in Windows 7 does not benefit to Pegasus2 M4 because it is recognized as SAS device by operating system.
In Windows 8.1 and Windows 10, TRIM feature is supported for SAS device and the setting is always enabled by default. Pegasus2 M4 SSD fully function with TRIM feature in these two operating systems.