Starting with Windows 10 build 1809, Microsoft has changed the default write policy for USB and Thunderbolt connected storage from Better Performance to Quick Removal.
As a result any connected Pegasus3 or Pegasus32 will have slower write performance.
Setting the write policy to Better Performance:
First, attach your Pegasus3 or Pegasus32 Thunderbolt cable to the Windows 10 computer and grant access to the storage.
Next, right click on the Start area and select Device Manager.
Select Disk Drives > Promise Pegasus3 R8 SCSI Disk Device > Properties
Change the Removal policy to Better Performance and Enable write caching on the device.
Click the OK button to save the changes.
For users with the latest Pegasus3 or Pegasus32 firmware, driver and Pegasus Utility
If the Pegasus firmware is version 6.04.0000.18 or newer and the latest Pegasus Utility is used, the write cache policy can be set from the Pegasus Utility.
To change the policy, first start the Pegasus Utility, select the Logical Drive > Settings.
Then change the write policy from WriteThru to WriteBack.
And click Save.
You have now changed the Windows Write Policy for your Pegasus3 or Pegasus32.