A long way off in late 2010 or early 2011

A long way off in late 2010 or early 2011, the Sparc Enterprise server lineup gets a speed boost to 3 GHz with the Jupiter-E chips.

After that, in 2012, Sun has made no commitment to the kicker line of Fujitsu "Advanced Product Line 2" servers coming from Fujitsu. These APL2 machines are presumably to be based on the "Venus" eight-core Sparc64-VIII processor, which has a Sparc64-VIIIfx variant aimed at supercomputers. That Sparc64-VIIIfx chip will be used in a 10 petaflops massively parallel machine being built by Fujitsu and paid for by the Japanese government under the 1.2bn Project Keisoku effort.

All of this is subject to change, and some of it most certainly will once Oracle takes control of Sun.