Athlon 650 To 1400: June 2000 To June 2001
Unlike the Athlon K75 with the Orion core, the Thunderbird version of the Athlon includes an integrated 256 kB L2 cache running at full clock speed. There were two basic versions of the Thunderbird: 100 MHz FSB and 133 MHz FSB; the latter are available only from 900 MHz. Both of these versions were popularly referred to by the letters "B" (100 MHz) and "C" (133 MHz). This is the CPU that's gained AMD its worldwide reputation for fast and, above all, well-priced processors. Around this time, even computer users on a tight budget were able to play in the big league. It soon became apparent that the top-performing 1400 MHz Athlon was extremely power-hungry; thermal dissipation of the 0.18 micron CPU was rated at 72.1 W.
The top model with Thunderbird core: the AMD Athlon 1400.