Windows 3.1 build 31 is a pre-release build of Windows 3.1. It was mentioned in PX03461 from July 1991. The article compares the performance of SmartDrive (codenamed Bambi) running on both Windows 3.1 build 31 and IBM OS/2 2.0 build 6.138, while new tests are being made on build 6.149.
