• Update Date: March 7, 2025 by Dave Farquhar
• IBM 5150 Revision A vs B: October 27, 1982 is the date on the IBM 5150 Revision B BIOS. Can't tell the difference from the front. Back differences: Revision B has "b" in a circle and 5 screws (or positions), while Revision A has no marking and only 2 screws. Power supply of original 5150 is black.
• Advantages and Disadvantages of IBM PC 5150 Revision A: Collectibly more interesting as older and scarcer. More likely to have single-sided floppy drives and early motherboard taking 16-64K RAM. But has memory limitations (upper limit 544K due to early BIOS), single-sided floppy drives with half storage capacity, and may limit software use. Perfect for historical artifact but not for running later software.
• Advantages and Disadvantages of Revision B IBM PC 5150: Better compatibility with full 640K memory, more likely to have 360K drives and a long shot of 720K floppy. Can run most software without 286 requirement. Good for those wanting a machine like original IBM PC but with later capabilities. Downside is not rare and has a price premium over 5160.
• Production and Sales: IBM sold 3.3 million 5150s and 2.1 million 5160s. Revision A had a production run of about 18 months (ending in March 1983) and total sales around 600,000. Revision B had a 4-year production run and about 2.7 million exist. There are about 600,000 fewer 5160s than Revision B 5150s.
• Pragmatic View: From a practical stand, the best IBM PC is the one with a price tag ready to buy. The author has a 5170 and a Tandy 1000 and doesn't need a 5150.
• Author Info: David Farquhar is a computer security professional, entrepreneur, and author. Writing about computers since 1991, working in IT since 1994 and specializing in vulnerability management since 2013. Holds Security+ and CISSP certifications and blogs five times a week about retro computers and gaming from 1975 to 2000.