New and improved CPU support

OpenSolaris 2010.03 will support for two new generations of processors, one SPARC and one AMD X86. Fault management will also be enhanced for the upcoming Intel Nehalem EX.

Rainbow falls or perhaps "UltraSPARC T3"
Support for the next generation of CMT processors from Sun planned for 2010 was added to build 131. This new chip will have 16 cores with 8 (or even 16?) threads each. No public PSARC or bugid is available, but here is the putback:
PSARC 2009/177 Solaris support for Rainbow Falls platforms
Here is a presentation of the CPU from the hotchips conference:
Sun's Next Generation CMT Processor

AMD Magny-Cours processor
A 8-12 core CPU that should appear in 2010, the following changes was integrated into build 128:
6843035 Need support for Magny-Cours processors
6860401 FMA CPU Topology & Memory Topology needs to support Magny Cours (Multi chip Module)

Intel Nehalem EX
Intel next Xeon CPU with 8 cores, 2 threads per core. Is also supported in OpenSolaris 2009.6 but FMA was added in b127:
FMA for Intel Nehalem EX
There is also a whitepaper on Nehalem support in OpenSolaris, worth a read:
The Solaris OS and Intel Nehalem EX