Editing IBM PS/2 Model 80 (section)

== Planar Types ==

{| class="wikitable styled-table" style="width:100%;"
|+'''8580 planars'''
! style="text-align:left;" | Type !! style="text-align:left;" | Speed !! style="text-align:left;" | Models !! style="text-align:left;" | FRU !! style="text-align:left;" | Memory connectors
|-
| Type 1 || 16 MHz || -041, -071 || 33F8416 (P/N 72X7492) || J15, J16
|-
| Type 2 || 20 MHz || -081, -111, -121, -161, -311, -321 || 33F8506 / 92F0756 / 92F0767 (P/N 90X7390) || J15, J16
|-
| Type 3 || 25 MHz || -A16, -A21, -A31 || 34F0022 (P/N 33F5571) or 85F0046 (P/N 91F7513) || J8, J9
|}

<ref name="at8580t1" /><ref name="at8580t2" /><ref name="at8580t3" />

The 25 MHz planar is a Japanese design — it is the board used in the PS/55 Model 5570-Vxx — and it shares its core logic with the 25 MHz [[IBM PS/2 Model 70|Model 70]] planar rather than with the earlier 8580 boards.<ref name="at8580t3" />

The two base frame assemblies are '''not interchangeable'''. FRU 64F0157 is used on the -041 through -321 and contains a metal back plane required for EMC, which should not be removed. FRU 64F0158 is used on the -A16, -A21 and -A31 and has no back plane, because that planar has components on its solder side.<ref name="at8580c" />