Does AMD officially produce a Barton core of the Athlon XP 2600+. I cant find it listed in any roadmaps, but i seem to have one. CPU-Z identifies it and it has a 512K L2 Cache. What gives.

Barton goes up to 2500 as far as I know. Maybe an accidental overclock?

Officially Barton comes in 2500, 2800, 3000, 3200.
Also the clock speed isnt above normal (although it overclocks very well it seems. I've barely done anything and its running at a 400MHZ overclock). But the L2 cache is at the normal barton level.

Yes, there is an Athlon 2600+ Barton, 333Mhz FSB, 512 L2 cache.
http://www.newegg.com/app/ViewProductDesc.asp?description=19-103-418&depa=1