AMD Athlon processor family is a line of high- performance processors based on AMD K7 architecture. Earlier Athlon processors with backside L2 cache were produced in a Card Module package. With the introduction of a Thunderbird core, which added on-die 256 KB L2 cache, it became possible to package the processors into smaller and cheaper PGA package. Because the L2 cache on Thunderbird Athlon CPUs is running at the same speed as the processors, T-Bird Athlons are faster than slot A Athlons with their slower L2 cache. Athlon microprocessors received another performance boost when their bus frequency was increased from 200 to 266 MHz. The fastest processors from the AMD Athlon CPU family are 1.4 GHz A1400AMS3C with 266 MHz front side bus (FSB) and 1.4 GHz A1400AMS3B with 200 MHz FSB.