Enhanced processor compatibility modes

The POWER6® enhanced and POWER6+™ enhanced processor compatibility modes provide additional floating-point instructions to applications that use the POWER6 or POWER6+ processor.

If you want a logical partition to run in an enhanced mode, you must specify the enhanced mode as the preferred mode for the logical partition. If the operating environment supports the corresponding non-enhanced mode, then the hypervisor assigns the enhanced mode to the logical partition when you activate the logical partition. In other words, if you specify the POWER6+ enhanced mode as the preferred mode, and the operating environment supports the POWER6+ mode, the hypervisor assigns the POWER6+ enhanced mode to the logical partition when you activate the logical partition. Similarly, if you specify the POWER6 enhanced mode as the preferred mode, and the operating environment supports the POWER6 mode, the hypervisor assigns the POWER6 enhanced mode to the logical partition when you activate the logical partition.

Logical partitions in the POWER6 enhanced processor compatibility mode can only run on POWER6 processor-based servers, and logical partitions in the POWER6+ enhanced processor compatibility mode can only run on POWER6+ processor-based servers. Therefore, if a logical partition runs in the POWER6 enhanced mode, you can only move the logical partition to POWER6 processor-based servers. Likewise, if a logical partition runs in the POWER6+ enhanced mode, you can only move the logical partition to POWER6+ processor-based servers. If you want to move a logical partition in the POWER6 enhanced processor compatibility mode to a POWER6+ processor-based server, then you need to change the preferred mode to the default or POWER6 processor compatibility mode and restart the logical partition.