Thanks xStainDx...There are a lot of concerns in regards availability and pricing of AMD's next generation x86-64 processors these days. Since AMD has been postponing their code-named K8 aka Hammer CPUs for ages now, a lot of analyst suppose that the company experiences lower than expected yields for these chips in addition to the very complex design of such devices with SOI technology.
As well as everything else mentioned above, there are also rumours that AMD may launch more advanced Athlon64 processors with 1MB of L2 cache instead of the CPUs but with 256KB of cache. The move will definitely not allow AMD to offer a lot of its x86-64 products from the early beginning.
At the moment AMD's Fab 30 can produce up to 5000 wafers per week, according to AMD's web-site. Given that the core size of the Thoroughbred is about 84 square millimetres, we can count that from a 8-inch wafer we get about 325 cores.
There is information that currently AMD's yield for the Thoroughbred core based Athlon XP CPUs is approximately 60% (the final yield is meant here and below), thus, only 195 cores make it to become microprocessors. I remember that the original size of the Athlon64 (ClawHammer) and Opteron (SledgeHammer) core was 104 and 200 square millimetres respectively.
News source: Neowin BPN Forum