IBM Power 780 Technical Overview And Introduction page 148

The Power 780 allows up to 128 cores in a single system, supporting the following
maximums:
Up to 128 dedicated partitions
Up to 1000 micropartitions (maximum 20 micropartitions per physical active core)
An important point is that the maximums stated are supported by the hardware, but the
practical limits depend on application workload demands.
Note the following additional information about virtual processors:
A virtual processor can be running (dispatched) either on a physical processor or as
standby waiting for a physical processor to became available.
Virtual processors do not introduce any additional abstraction level. They are only a
dispatch entity. When running on a physical processor, virtual processors run at the same
speed as the physical processor.
Each partition's profile defines CPU entitlement that determines how much processing
power any given partition should receive. The total sum of CPU entitlement of all partitions
cannot exceed the number of available physical processors in a shared processor pool.
The number of virtual processors can be changed dynamically through a dynamic
LPAR operation.
Processing mode
When you create a logical partition you can assign entire processors for dedicated use, or you
can assign partial processing units from a shared processor pool. This setting defines the
processing mode of the logical partition. Figure 3-7 shows a diagram of the concepts
discussed in this section.
lp lp lp lp
Dedicated processors
Figure 3-7 Logical partitioning concepts
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IBM Power 770 and 780 (9117-MMD, 9179-MHD) Technical Overview and Introduction
Set of micro-partitions
lp lp lp lp lp lp
vp vp
lp lp
Shared-Processor Pool 0
POWER Hypervisor
Dedicated processors
8-core SMP System
Set of micro-partitions
lp lp lp lp
vp vp vp
Shared-Processor Pool 1
KEY:
vp Virtual processor
lp Logical processor
PrU Processing Units
lp lp
vp