Grab a copy from here. We have been playing with Magny Cours and Istanbul for a while, and will be generating a number of white papers around these efforts. Comparisons to Nehalem of similar clock speed, and if available, other units.
Magny Cours is a very interesting chip. 12 processor cores in a single socket. This has some interesting implications for performance, and you have to pay attention to things you might not have thought you needed to before. A subsequent paper will cover this.