Looks like Intel Potomac server family is delayed once more, and is now expected in Q2 rather than Q1 next year. But there's some good news for Xeons:
"Xeons using the Lindenhurst E7520 chipsets, some of which we saw at Computex, will debut at speeds of 3.60GHz, but will reach 4GHz by the first quarter of 2005. These are Irwindales, using the 90 nano core, 800MHz front side bus, with 2MB L2 caches, and using Intel Extended Memory 64 tech with 2MB."
Updated Intel Roadmap here. Article here.
You may also want to read an article here on AMD's Sempron.