Owner`s manual

As Figure 1–2 shows, three factors affect the customer’s choice between the
two ways of upgrading to a VAX 6000 Model 500 from a Model 200, 300, or
400 with an XMI that does not have +3.3V power.
Need for Battery Backup
The H7231-N battery backup unit (used with the VAX 6000 Model 200,
300, or 400 systems without a +3.3V XMI) is incompatible with the
KA65A processor. An H7236-A battery backup unit is required, and its
installation entails the full power and packaging upgrade (the H9657-
CU kit).
Need for More Than Four CPUs
The H9657-CX kit generates enough +3.3V power to run four KA65A
CPUs. If you need more than four CPUs, you must perform the full
power and packaging upgrade, where you install the H7242 power
regulator.
Need for More Than 12 XMI Slots
The H9657 power regulator module requires two XMI slots, leaving 12
slots for processors, memories, and adapters. If you need more than 12
slots, you must install the full power and packaging upgrade.
If the customer does not need the three items mentioned, option ,
installing the H9657-CX kit is probably the best choice. If the customer
needs any of the three items, option is needed. This upgrade is described
in detail in the VAX 6000 XMI Conversion Manual.
Introduction 1–5