The Power5+ Processor - IBM System p5 550 Technical Overview And Introduction

2.1 The POWER5+ processor

The POWER5+ processor capitalizes on all the enhancements brought by the POWER5
processors. For a detailed description of the POWER5 processor, refer to IBM Eserver p5
550 Technical Overview and Introduction, REDP-9113. Figure 2-2 shows a high-level view of
the POWER5+ processor.
Figure 2-2 POWER5+ processor
The CMOS10S technology in the POWER5+ processor uses a 90 nm fabrication process,
which enables:
Performance gains through faster clock rates
Physical size reduction (243 mm compared with 389 mm)
The POWER5+ processor is 37% smaller than the POWER5 processor. It consumes less
power and requires less cooling. Thus, you can use the POWER5+ processor in servers
where previously you could only use lower frequency chips due to cooling restrictions.
The POWER5+ design provides the following additional enhancements:
New pages sizes in ERAT and TLB. Two new pages sizes (64 KB and 16 GB), which were
recently added in the PowerPC® architecture.
New segment size in SLB. One new segment size (1 TB) recently added in PowerPC
architecture.
The TLB size has been doubled in the POWER5+ over the POWER5 processor. The TLB
in POWER5+ has 2048 entries.
Floating-point round to integer instructions. New instructions (frfin, frfiz, frfip, and frfim)
have been added to round floating-point numbers integers with the following rounding
modes: nearest, zero, integer plus, and integer minus.
Improved floating-point performance.
Lock performance enhancement.
Enhanced SLB read.
True Little-Endian mode. Support for the True Little-Endian mode as defined in the
PowerPC architecture.
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IBM System p5 550 and 550Q Technical Overview and Introduction
POWER5+ Processor POWER5+ Processor
Core Core Core
2.1 GHz 2.1 GHz 2.1 GHz
L3 L3
L3 L3
1.9 MB L2 1.9 MB L2
Intf Intf
Bus Bus
Mem Mem
Enhanced Distributed Switch Enhanced Distributed Switch
Mem Mem
Bus Bus
Cntrl Cntrl
GX+ GX+
Core Core Core Intf Intf
2.1 GHz 2.1 GHz 2.1 GHz
(Fabric Bus Controller) (Fabric Bus Controller)
Vertical Vertical
Fabric Fabric
Bus Bus
GX+ GX+
Bus Bus
SMP SMP
Fabric Fabric
Bus Bus