Aces hardware has some info about Niagra, a processor that sun are making that will have 8 cores and 4 threads per core. this is, as far as i can gather, 8 hyperthreading processors in one, with hyper threading enabled for 4 threads not the usual 2 in the P4/Xeon.

Sun is currently projecting that Niagara will have 15x the server performance of their current server blade processor, the 650MHz UltraSPARC IIi. That would be competitive with 4-way servers using 130nm Opterons and Xeon MPs, and likely well above them in more network intensive benchmarks. By the time it’s released, Niagara will probably be competing with high-end 2-way servers using 90nm processors. </p> Sounds like a nice processor, but not SMP enabled, but would you need it for a chip like that?!