The K8: AMD Moves To 64 Bits
K8 was the first x86 processor compatible with 64-bit addressing. The architecture had other advantages such as an integrated memory controller. AMD has released a veritable army of K8-based processors since then, but we’ll concentrate on the models intended for the mainstream: the Athlon 64s. In practice, the Opteron (the server version), Athlon 64 FX (high-end) and Turion 64 (for mobile PCs) are very closely related. In general, they differ only in the management of the memory controller and cache memory, plus the type of memory used.
| Code name | ClawHammer | Orleans |
| Date released | 2003 | 2006 |
| Architecture | 64-bits | 64-bits |
| Data bus | 64-bits | 64-bits |
| Address bus | 64-bits | 64-bits |
| Maximum memory | 1 TB | 1 TB |
| L1 cache | 64 KB + 64 KB | 64 KB + 64 KB |
| L2 cache | 1,024 KB (CPU frequency) | 512 KB (CPU frequency) |
| Clock frequency | 1,800-2,400 MHz | 1,800-2,600 MHz |
| memory controller | DDR-400, 1 channel | DDR2-667, 2 channel |
| FSB | 800 MHz (HTT) | 1,000 MHz (HTT) |
| FPU | built-in | built-in |
| SIMD | MMX, Enhanced 3DNow!, SSE, SSE2 | MMX, Enhanced 3DNow!, SSE, SSE2, SSE3 |
| Fabrication process | 130 nm | 90 nm |
| Number of transistors | 105.9 million | 81.1 million |
| Power consumption | 89 W (TDP) | 62 W (TDP) |
| Voltage | 1.5 V | 1.25-1.4 V |
| Die surface area | 193 mm² | 103 mm² |
| Connector | Socket 754 | Socket AM2 |
Athlon 64 processors still use a PR number to indicate their ranking in the product range and there are many different versions, which generally differ in terms of cache memory and/or fabrication process. We highlighted only two models, but there are a dozen or so different K8 versions for the standard Athlon 64 alone.