Am386DX-40 ten years earlier. AMD's new fab facility in Dresden increased production for AMD overall and put out Thunderbirds at a fast rate, with the process technology improved by a switch to copper interconnects. After several versions were released in 2000 and 2001 of the Thunderbird, the last Athlon processor using the Thunderbird core was released in 2001 in the summer, at which point speeds were at 1.4 GHz. The locked multipliers of Socket A Thunderbirds could often be disabled through adding conductive bridges on the surface on the chip, a practice widely known as "the pencil trick". Specifications L1-cache: 64 + 64 KB (data + instructions) L2-cache: 256 KB, full speed MMX, 3DNow! Slot A & Socket A (EV6) Front-side bus: 100 MHz (Slot-A, B-models), 133 MHz (C-models) (200 MT/s, 266 MT/s) Vcore: 1.70–1.75 V First release: June 4, 2000 Transistor count: 37 million Manufacturing process: 0.18 μm/180 nm Clock rate: Slot A: 650–1000 MHz Socket A, 100 MHz FSB (B-models): 600–1400 MHz Socket A, 133 MHz FSB (C-models): 1000–1400 MHz Athlon XP (2001–2003) Overall, there are four main variants of the Athlon XP desktop CPU: the Palomino, the Thoroughbred, the Thorton, and the Barton. A number of mobile processors were also released, including the Corvette models, and the Dublin model among others. Palomino On May 14, 2001, AMD released the Athlon XP processor. It debuted as the Mobile Athlon 4, a mobile version codenamed Corvette, with the desktop Athlon XP released in the fall. The third-generation Athlon, code-named Palomino, came out on October 9, 2001, as the Athlon XP, with the suffix signifying extended performance and unofficially referencing Windows XP. Palomino's design used 180 nm fabrication process size. The Athlon XP was marketed using a performance rating (PR) system comparing it to the Thunderbird predecessor core. Among other changes, Palomino consumed 20% less power than the Thunderbird, comparatively reducing heat output, and was roughly 10% faster than Thunderbird. Palomino also had enhanced K7's TLB architecture and included a hardware data prefetch mechanism to take better advantage of memory bandwidth. Palomino was the first K7 core to include the full SSE instruction set from the Intel Pentium III, as well as AMD's 3DNow! Professional. Palomino was also the first socketed Athlon officially supporting dual processing, with chips certified for that purpose branded as the Athlon MP (multi processing), which had different specifications. According to HardwareZone, it was possible to