PowerMacG5 Late 2005

The Power Macintosh G5 \"Quad Core\" (2.5) stands as a unique model in Apple's history, being part of the first and only series of Power Macintosh G5s to use dual-core PowerPC 970MP (G5) processors. These CPUs innovatively placed two independent processor \"cores\" on a single silicon chip. This model shared its dual-core architecture with the 2.0 GHz and 2.3 GHz versions.\n\nThe \"Quad Core\" (2.5) model was powered by two \"dual core\" 2.5 GHz PowerPC 970MP (G5) processors, resulting in a total of four cores. This setup included four optimized AltiVec \"Velocity Engine\" vector processing units (one per core), eight double-precision FPUs (two per core), 1 MB of on-chip level 2 cache per core, and dual bidirectional 1.25 GHz frontside system buses (one for each physical processor). It shipped with 512 MB or 1 GB of 533 MHz PC2-4200 DDR2 SDRAM, a 250 GB Serial ATA hard drive (7200 RPM), a \"16X\" dual-layer \"SuperDrive,\" and an NVIDIA GeForce 6600 graphics card with 256 MB of GDDR SDRAM.\n\nConnectivity was extensive, featuring USB 2.0, FireWire \"400\" and \"800,\" a single-link DVI and a dual-link DVI port, optical digital audio in/out, dual independent Gigabit Ethernet ports, and support for AirPort Extreme (802.11g) and Bluetooth 2.0+EDR.\n\nAll \"multiple core\" G5 models were equipped with three open PCI-Express (PCIe) expansion slots. While using the same easy-to-upgrade \"anodized aluminum alloy\" case with a removable side panel, the \"Quad Core\" model required an advanced liquid cooling system, replacing the traditional heat sink to manage the immense thermal output from its two dual-core processors.

The Power Macintosh G5 \"Quad Core\" (2.5) was the final and most powerful PowerPC-based computer Apple ever released, representing the absolute zenith of the G5 architecture. It was praised as a 'magnificently powerful' workstation, delivering massive performance gains that could justify its cost for professionals through productivity enhancements alone. The performance was so compelling that it forced serious consideration even with the knowledge that the Intel transition was imminent. This model featured a more reliable, Panasonic-built liquid cooling system (LCS) compared to the leak-prone Delphi units in earlier high-end G5s. However, despite being an improvement, the LCS remained the machine's Achilles' heel; over its long life, it could still degrade, leading to overheating and fan noise issues that required complex servicing. It stood as a testament to the brute-force power of the PowerPC but also highlighted the thermal challenges that ultimately prompted Apple's switch to a more power-efficient architecture.