According to The Inquirer's articles, Sledgehammer server chips will launch in Q1 at speeds of 1.4 and 1.6GHz, with 1.8 and 2.0GHz variants coming in Q2. A version of Sledgehammer targeted at single-processor workstations will also appear in Q2. In 2004, AMD is apparently set to introduce 0.09-micron SOI Hammer processors that support DDRII-400.
It will be interesting to see just how competitive Opteron server processors will be at only 1.4 and 1.6GHz. Given AMD's current position, launching early and a little slow is probably better than holding off and waiting for yields of 2GHz chips to improve.