AMD Opteron 1.6 GHz
Known as the 'Third Generation' Opteron. It is the first quad-core Opteron that is based on AMD's first quad-core design 'Barcelona' (also known as K10-architecture).
Unfortunately AMD had problems getting the Barcelona to the market. It didn't deliver the performance that was needed to compete with Intel and it turned out that the Opteron was plagued by a bug in the translation lookaside buffer (B2-stepping and older). The bug was fixed/avoided with a BIOS patch but at the cost of performance. Later B3-revisions didn't have the bug.
AMD started shipping K10 Opteron's in September 2007. This particular sample is from the 21th week of 2007 which is late May 2007.