Mike at the gang at The Inquirer have been serving up regular, tasty morsels of AMD info, including this bit about AMD's plans for 940-pin (and later 939-pin) variants of the Athlon 64. The original plan for the Athlon 64 was to use a 754-pin socket and a single-channel memory connection. Now it looks like AMD may use the 940-pin socket for some top-end Athlon 64 chips. (Apparently the 939-pin socket will come into play so AMD can maintain the divide between Opterons and Athlons and so protect the Opteron's much healthier margins.) The move to the Opteron-style socket means, quite likely, that some Athlon 64 chips will arrive with dual-channel memory support.
Based on the proportion of Athlon 64s likely to be 940-pin chips versus 754-pin chips (reportedly a 9:1 initial ratio in favor of the 754-pin chips), it's sounding like the dual-channel Athlon 64 will be a fairly rare, fairly expensive beastmuch like the first T-bred Athlon XP 2800+ or maybe the current Athlon XP 3200+. Taking into account Hammer's 12-stage pipeline, its more advanced but more difficult SOI fab process, current Opteron speeds, and the power of pure speculation, my best guesstimate is that this first high-end Athlon 64 will run at 2.2GHz and be rated at 3400+. Odds are that all Athlon 64 chips will support DDR400 memory speeds, as well. Given dual channels of DDR400 memory and all the natural advantages of the Hammer architecture, I wouldn't be surprised to see this 3400+ chip stack up well against Intel's Prescott-based Pentium 4 3.4GHz in performance. Even without 64-bit executables.
Speaking of which, Microsoft seems to be in no hurry to produce a final 64-bit version of Windows for AMD's new CPUs. With rumors pointing to a 2004 release date, the Athlon 64 will probably have to make do on the strength of its 32-bit performance (and the promise of unspecified joy at a later date) during the Christmas buying season.
September 23rd is also do-or-die date, in my book, for AMD's True Performance Initiative. We checked in with AMD about TPI's status some months back, and it was still alive and kicking then. If AMD can't pull together an announcement or articulate a clear roadmap toward a new performance metric when the Athlon 64 hits, I doubt it will ever happen.