Specifications

44 IBM Power 770 and 780 Technical Overview and Introduction
2.1.4 Memory access
Each POWER7 processor chip has two DDR3 memory controllers, each with four memory
channels (enabling eight memory channels per POWER7 processor). Each channel operates
at 6.4 GHz and can address up to 32 GB of memory. Thus, each POWER7 processor chip is
capable of addressing up to 256 GB of memory.
Figure 2-5 gives a simple overview of the POWER7 processor memory access structure.
Figure 2-5 Overview of POWER7 memory access structure
2.1.5 Flexible POWER7 processor packaging and offerings
POWER7 processors have the unique ability to optimize to various workload types. For
example, database workloads typically benefit from very fast processors that handle high
transaction rates at high speeds. Web workloads typically benefit more from processors with
many threads that allow the breaking down of web requests into many parts and handle them
in parallel. POWER7 processors uniquely have the ability to provide leadership performance
in either case.
TurboCore mode
Users can opt to run selected servers in TurboCore mode. It uses four cores per POWER7
processor chip with access to the full 32 MB of L3 cache (8 MB per core) and at a faster
processor core frequency, which might save on software costs for those applications that are
licensed per core.
Note: In certain POWER7 processor-based systems, one memory controller is active with
four memory channels being used.
POWER7 Processor Chip
Advanced
Buffer ASIC
Chip
Memory
Controller
Advanced
Buffer ASIC
Chip
Memory
Controller
Core Core Core Core
Core Core Core Core
Dual Integrated DDR3 memory controllers
• High channel and DIMM utilization
• Advanced energy management
• RAS advances
Eight high-speed 6.4 GHz channels
• New low-power differential signalling
New DDR3 buffer chip architecture
• Larger capacity support (32 GB/core)
• Energy management support
• RAS enablement
DDR3 DRAMs