I purchased late last year what I believed to be an AMD 2600+ processor, and earlier in the year an AMD 2100+. I've just received another processor, but it's spec was not showing up correctly, so I had a look at AMD's site and found the CPU Information util (on this page: http://www.amd.com/us-en/Processors/...1_2364,00.html
) ... running it on the first 2600+ and the 2100+ processor machines I find they're both running at ~1260MHz and the processor information is simply "AMD Athlon AuthenticAMD". The newer chip which was supposed to be a 2600+ but is actually a 2000+ runs at 1665MHz and has "AMD Athlon XP 2000+ Authentic" tag ... this leaves me with the question "What the heck are my first two processors??".
I have 300 watt power supplies in the machines that are running at ~1260MHz and have let the motherboards on "auto configure" jumper settings.