The History Of AMD CPUs

AMD K6-II+ And K6-III+

The last processors released by AMD in the K6 product line were the K6-II+ and K6-III+, which were targeted at the mobile market. These processors were similar to the K6-III in that they incorporated on-die L2 cache. The K6-II+ had 128 KB of L2, whereas the K6-III+ had 256 KB. Thanks to the use of AMD's 180 nm fab technology, these processors were relatively energy efficient.

AMD K6-II+ And K6-III+

AMD K7 And K75: The Birth Of Athlon

In 1999, AMD released its seventh-generation processor, the Athlon. It used a new architecture that increased IPC considerably and allowed AMD to push the clock rates up to 1 GHz. The FPU inside of AMD's previous processors had lagged behind competing Intel products, so improving the FPU was one of the primary objectives of the design team. This lead to the Athlon being equipped with an exceedingly powerful triple-issue out-of-order FPU that surpassed Intel's competing processors.

The first processor models placed the CPU core on a large silicon card. Instead of using on-die L2 cache, AMD used separate RAM chips soldered onto the same package as the CPU. This enabled AMD to install larger amounts of L2, but the cache ran at lower clock speeds.

Licensing DEC's EV6 FSB technology allowed AMD to design its own chipsets, leading to the first all-AMD platforms. Unfortunately, those first motherboards fell short of what Intel's competing 440BX could do. The EV6 FSB also made the Athlon compatible with new DDR RAM, which featured greater bandwidth and performance compared to traditional SDRAM.

AMD K7 And K75

AMD K7: Athlon Thunderbird

Not long after the release of AMD's Athlon on Slot A and Intel's Pentium II and III for Slot 1, the industry realized that the lackluster performance of the L2 cache was hampering CPU performance. To overcome this issue, AMD reverted back to a traditional processor package with its Athlon Thunderbird, which contained L2 cache integrated directly onto the CPU die. Although the L2 cache size was cut in half, it ran at the same speed as the CPU, drastically improving performance.

Thanks to a maturing 180 nm process and higher yields, AMD also took this opportunity to boost the clock speed of its CPUs by 400 MHz.

AMD Athlon Thunderbird

K7: AMD Duron

To target the entry-level segment and to make use of its lower yield chips, AMD introduced the Duron product line. These processors used the same architecture but generally ran at lower clock speeds. AMD also disabled all but 64 KB of the L2 cache on these processors, which reduced performance, but the Duron still was quite competitive against Intel's Celeron products.

AMD Duron

AMD K7: Athlon Palomino/XP

In 2001, AMD improved the Athlon again with the Palomino/XP. Little changed between the Thunderbird and the Palomino/XP, but the ever-maturing 180 nm process enabled AMD to push clock speeds up another 333 MHz. It also added support for the SSE SIMD instruction set. Microsoft's Windows XP launched around the same time, so AMD added "XP" to the Palomino code name to help advertise it towards users of the new operating system.

Versions of the Athlon Palomino/XP were also sold under the name "Athlon MP" for servers and "Athlon 4" or "Athlon XP Mobile" for laptop computers.

AMD Athlon Palomino/XP

AMD K7: Athlon Thoroughbred And Barton

In 2002, AMD rolled out the Athlon Thoroughbred, which was produced on a new 130nm process. This helped lower power consumption push frequencies over 2 GHz. As the process matured, AMD introduced the Barton a year later. Barton brought a modest clock rate increase, and it also doubled the size of the L2 cache and added support for 200 MHz FSB and 400 MHz DDR RAM.

AMD Athlon Thoroughbred and Barton

AMD K7: Athlon Thorton And Duron

Alongside Barton, AMD released two lower-end processors, the Athlon Thorton and a new Duron. Both processors used the same die as Barton but with part of the L2 cache disabled.

Thorton had 256 KB of L2 cache. similar to older Athlon processors, and it ran at slightly lower clock speeds than Barton. Thanks to the new 130nm fab technology, it was also more energy efficient than the older Athlon CPUs. The new Duron chip was limited to 64 KB of L2 cache, just like the previous Duron processors, but it was available at clock speeds up to 1.8 GHz, making the high-end models considerably faster than their predecessors.

AMD Athlon Thorton and Duron

AMD Geode: The APU Predecessor

AMD purchased the Geode processor line in 2003 from National Semiconductor to extend its low-end product offerings. The Geodes actually had roots in another company called Cyrix, which created the MediaGX product line in the late 1990s as a single-chip solution containing a general-purpose processor, sound chip, graphics accelerator and all of the hardware typically inside of a motherboard's chipset. When Cyrix went out of business, National Semiconductor picked up the MediaGX and transformed it into the Geode.

AMD launched two processors under the "Geode" name. At the extreme low-end was the Geode GX series, which was identical to the products sold by National Semiconductor. As a somewhat higher-performance solution, AMD also introduced the LX series, which contained several enhancements including the transition to AMD's K7 Athlon architecture for the CPU. These products were highly efficient and were used in several inexpensive and thin-client devices.

AMD Geode

AMD K7: First Sempron

AMD released its first Sempron-branded products in 2004. Initially, they slid in between the high-end Athlon Barton processors and the low-end Duron, filling roughly the same space as the Athlon Thorton. The first few models used either Thorton or Thoroughbred cores with the full 256 KB of L2 cache. These chips were capped at slightly lower clock speeds, with the fastest SKUs clocked at 2 GHz.

Just a few months after Sempron was introduced, AMD released a new version based on the Barton core with the full 512 KB of L2 cache and a higher 2.2 GHz clock speed.

AMD Sempron

AMD K8: Athlon 64!

In 2003, AMD shocked the world by introducing the first consumer-oriented 64-bit x86 processor. Codenamed "K8," these processors were essentially heavily modified variations of the K7. By moving to a 64-bit design, AMD was able to extend the memory support to a theoretical 1 TB.

Although that was more RAM than any K8 system would ever use, PCs were no longer limited to 4 GB of memory, and systems with 8 GB of RAM began showing up on the market. AMD also moved the memory controller from its chipset and integrated it into the CPU die. This drastically reduced memory latency and pushed performance up considerably over the K7. With the memory controller inside of the CPU die, this effectively removed the FSB from the system. Instead, AMD introduced its HyperTransport technology, which was capable of significantly greater bandwidth than the older FSB connection.

AMD sold the initial batch of K8 chips under the brand names "Athlon 64" for consumers (Clawhammer and Newcastle), "Athlon 64 FX" (Sledgehammer and Clawhammer) for enthusiasts and "Opteron" for servers (Sledgehammer).

AMD Athlon 64 Sledgehammer, Clawhammer and Newcastle