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G3 Microprocessor

The processor in the iMac family of computers is a PowerPC G3 microprocessor. The G3 microprocessor has several features that contribute to superior performance, including:

• large on-chip (L1) caches, 32 KB each for instruction cache and data cache

• a built-in cache controller and cache tag RAM for the second level (L2) cache

• a separate backside bus for the L2 cache, providing faster clock speed and overlapped bus transactions

• a microprocessor core optimized for Mac OS applications

The G3 microprocessor in the iMac family of computers runs at a clock speed of 350 or 400 MHz.