Some steppings of the Athlon 64 3700+ (SanDiego 939) are reported to achieve over 3.1GHz on air cooling.
I just got an Athlon 64 3700+ (KACAE 0605APAW) from newegg.com for a new system I am building. (price for ADAFX55
BNBOX = $104.00 when I bought it, now $99.00; the BN is the good version)
I have read on other forums about the KACAE stepping which indicate that it does well overclocking (sometimes reaching 3.2GHz) on standard voltage and air cooling.
The link below has a well written article titled: "What are the different 3700+ San Diego steppings and how do they perform?" by Namrac
http://www.overclock.net/faqs/101138...san-diego.html
Some posts mention a "cold bug"; meaning that it does not do any better with cooling methods that are better than air cooling.
I hope to have the my system together in a couple of days. I'm waiting on a couple of parts.