Editing IBM PC XT Maintenance Guide (section)

== Identify Your Motherboard ==

Two motherboard revisions exist, identified by silkscreen marking near the keyboard port:

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''IBM 5160 motherboard generations'''
! Silkscreen marking !! RAM banks !! BIOS shipped !! Notes
|-
| 64-256KB (early) || 4 × 64 KB || 11/08/82 || Same motherboard found in the IBM 5155. IBM-supported modification possible to support 640 KB.
|-
| 256-640KB (later) || 2 × 256 KB + 2 × 64 KB || 01/10/86 or 05/09/86 || Native 640 KB. 1986 BIOSes may not support an IBM 5161 Expansion Unit.
|}

[[File:IBM 5160 motherboard 64-256KB silkscreen.jpg|center|thumb|400px|Silkscreen marking of the 5160 64-256KB motherboard (minuszerodegrees.net)]]
[[File:IBM 5160 motherboard 256-640KB silkscreen.jpg|center|thumb|400px|Silkscreen marking of the 5160 256-640KB motherboard (minuszerodegrees.net)]]

The BIOS in sockets U18 and U19 also identifies the build — see [[IBM PC XT (5160)#BIOS revisions|the product page]] for the four documented BIOS revisions and their part numbers.