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The PowerPC 970, developed by IBM and introduced in October, 2002, is the first 64-bit CPU to be shipped in a personal computer; namely, the PowerMac G5 introduced by Apple at the 2003 Worldwide Developer's Conference. When the chip was first announced, IBM boasted speeds of 1.4-1.8Ghz, though Apple is currently shipping models in 1.6-2.0Ghz configurations. Since the PowerPC was originally designed from the beginning be 64-bit capable, the 64-bit architecture is 100% backwards compatible with existing 32-bit applications with no performance penalty. Apple's first-generation PowerMac G5's have dual independent 1Ghz frontside buses (one for each processor).

The PowerPC 970 borrows its superscalar, superpipelined execution core from IBM's 64-bit POWER4 processor, to which Apple and IBM added their vector processing unit, the Velocity Engine. The PowerPC 970 uses less power and has a smaller die than the POWER4, and also features the ability to perform the same operation on multiple data elements (called SIMD). Both the POWER4 and the PPC 970 feature two double-precision floating-point units allowing for two or more 64-bit calculations in a single clock cycle. The POWER4 also had a dual core design with a shared level 2 cache, whereas the the PowerPC 970 has a single core design.

The 64-bit design gives ample room for memory expansion. Theoretically it can address up to 18 exabytes. In practice, it uses only 42 bits for addressing allowing up to 4 terabytes. Apple's PowerMac G5 allows for up to 8 gigabytes. The chip itself is 118 millimeters square, with over 58 million transistors, utilizing an additive-copper, dual-damascene wiring process, technology on a thin layer of silicon on insulator, with 130 nanometer spacing.

Benchmarks

(conducted by Apple with GCC 3.3)

SPECfp_rate_base2000:     15.7
SPECint_rate_base2000:    17.2
SPECfp_base2000:          840
SPECint_base2000:         800

I believe these were conducted on a dual 2Ghz Powermac G5. See SPEC.org for more information about the benchmarking suite.

References

"PowerPC G5." Apple. June 2003. 26 July, 2003. <http://www.apple.com/g5processor/>.

"PowerPC 970: First in a new family of 64-bit high performance PowerPC processors." IBM. October 15, 2002. 26 July, 2003. <http://www-3.ibm.com/chips/techlib/techlib.nsf/techdocs/A1387A29AC1C2AE087256C5200611780>.

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