The "XP" range of processors was released in October 2001 and supersedes the existing range of "Thunderbird" CPUs. Along with a slight optimisation of the core to improve performance and reduce power dissipation, the new "XP" chips no longer use their their name to denote their actual clock frequency. Instead AMD introduced a new naming convention which they call "True Performance Initiative". The idea being, the name now denotes the equivalent performance of a standard Athlon running at the indicated frequency. Confused? Taking the XP2100+ as an example, this chip runs at a frequency of 1.73GHz but supposedly has similar performance to a standard Athlon running at 2.1GHz. Judging from the reviews I have read, the new naming suggests equivalent competitors processors rather than Athlons. Opinions are divided as to whether or not this new naming convention is a good idea, the fact is an XP2100+ running @ 1.73GHz has exactly the same performance as an XP2100+ running @ 1.73GHz!

Moving swiftly on, here is a list of the XP processor range showing their actual clock frequencies.

AMD Athlon XP processor 2100+ operates at a frequency of 1.73GHz. (13x133MHz)
AMD Athlon XP processor 2000+ operates at a frequency of 1.67GHz. (12.5x133MHz)
AMD Athlon XP processor 1900+ operates at a frequency of 1.60GHz. (12x133MHz)
AMD Athlon XP processor 1800+ operates at a frequency of 1.533GHz. (11.5x133MHz)
AMD Athlon XP processor 1700+ operates at a frequency of 1.47GHz. (11x133MHz)
AMD Athlon XP processor 1600+ operates at a frequency of 1.40GHz. (10.5x133MHz)

The XP2100+ processor is the latest and probably the last of the CPUs from AMD to use the Palomino core, soon to be replaced with the new "Thoroughbred", as can be seen from the roadmap below. The chip has approximately 37.5 million transistors and is manufactured using AMD's state-of-the-art 0.18-micron copper process technology at AMD's Fab 30 wafer fabrication facility in Dresden, Germany. The soon to be released "Thoroughbred" will use 0.13-micron technology, allowing AMD to push their processor chips to even dizzier heights of performance. As this is probably the last of the chips to use this core, there is little point on going into the finer details of the technology since it is about to change. Those of you still left wanting to know the knitty gritty technical details.

The XP2100+ runs at 1.73GHz but has the same power spec as the Athlon XP2000+, so a CPU cooler that is AMD-approved for Athlon XP 2000+ will be fine for the XP 2100+. With a case temp of 23°C the chip idled at 33°C and rose to 38°C under full load when running Stability test 6.