We learned that Intel's next generation native quad-core with eight threads should end up faster than 45nm K10.5 marchitecture. This is based on initial tests that claim that K10.5 will end up 10 to 20 percent faster than the current K10-based Opterons and Phenoms.
At the same time, Nehalem will be a significantly bigger chip than the Shanghai generation 45nm K10.5 and it's likely to generate more heat.
Other sources are suggesting that Nehalem won’t make it in Q4 2008 and that real volume production starts in Q1 2009. This was the case with the 45nm transition when Intel managed to have some 45nm in workstation market and a single desktop CPU in 2007. Even today in the later part of Q1 2008 Intel struggles to ship any affordable quad-core based 45nm Yorkfield cores.
After all it looks like AMD will finally have something that can challenge Intel.