At last week's Linley Tech Processor Conference, IBM announced the successor to its PowerPC 440/464 CPUs, the PowerPC 476FP. Able to issue up to five instructions at a time and process instructions out of order, the 476FP will likely achieve industry-leading single-thread throughput for a CPU core. Having a nine-stage pipeline and implemented as a hard core, the 476FP is conservatively rated at 1.6GHz in IBM's 45nm SOI process. In this configuration, the core measures 3.6mm2 and consumes 1.6W. Customers can begin designing ASICs using the CPU in October. IBM expects the first 476FP-based products to qualify for production in 2010. A synthesizable version will also be available.
The most similar CPUs to the 476FP are the e500mc from Freescale and the CPU used in RMI's XLP832. To conserve power, Freescale limits the speed of the e500 to 1.5GHz in 45nm, and it can issue only two instructions per cycle. Interestingly, both the 476FP and the e500mc incorporate floating-point units. The XLP's CPU is billed as running at up to 2GHz. It's a four-issue machine and thus likely to deliver similar single-thread performance as the 476FP. Being multithreaded, it has the potential for greater throughput than the 476FP, however.
Among licensable CPU cores, the 476FP is most similar to ARM's Cortex-A9. Both IBM and ARM claim their processors achieve the same performance per MHz on small benchmarks. The processors have a similar number of pipeline stages, can issue a similar number of maximum instructions per cycle, and have similar branch prediction. The 476FP is likely to perform better on most real-world code. The A9 cannot sustain its peak issue rate because it can only decode two instructions per cycle, and the 476FP can issue more integer instructions per cycle. The A9, however, supports ARM's Neon instructions, which give it an edge for multimedia applications.
Chip designers seeking a fast CPU for integration in their ASICs and ASSPs will find the 476FP the top choice. Its PowerPC compatibility makes it particularly well suited to communications and enterprise applications where the architecture has a strong presence. A key ingredient in LSI's multicore architecture, the 476FP will distinguish LSI from its competitors. --Joe
Joseph Byrne, senior analyst
Get the complete details on the new LSI platform (two separate slide presentations) in the Linley Tech Processor Conference proceedings (free download)
The most similar CPUs to the 476FP are the e500mc from Freescale and the CPU used in RMI's XLP832. To conserve power, Freescale limits the speed of the e500 to 1.5GHz in 45nm, and it can issue only two instructions per cycle. Interestingly, both the 476FP and the e500mc incorporate floating-point units. The XLP's CPU is billed as running at up to 2GHz. It's a four-issue machine and thus likely to deliver similar single-thread performance as the 476FP. Being multithreaded, it has the potential for greater throughput than the 476FP, however.
Among licensable CPU cores, the 476FP is most similar to ARM's Cortex-A9. Both IBM and ARM claim their processors achieve the same performance per MHz on small benchmarks. The processors have a similar number of pipeline stages, can issue a similar number of maximum instructions per cycle, and have similar branch prediction. The 476FP is likely to perform better on most real-world code. The A9 cannot sustain its peak issue rate because it can only decode two instructions per cycle, and the 476FP can issue more integer instructions per cycle. The A9, however, supports ARM's Neon instructions, which give it an edge for multimedia applications.
Chip designers seeking a fast CPU for integration in their ASICs and ASSPs will find the 476FP the top choice. Its PowerPC compatibility makes it particularly well suited to communications and enterprise applications where the architecture has a strong presence. A key ingredient in LSI's multicore architecture, the 476FP will distinguish LSI from its competitors. --Joe
Joseph Byrne, senior analyst
Get the complete details on the new LSI platform (two separate slide presentations) in the Linley Tech Processor Conference proceedings (free download)
Source: http://blog.linleygroup.com/2009/09/ibm-introduces-new-powerpc-cpu-core.html
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