I've updated the optimized miner to b15.  This version currently works only on Linux - I would greatly appreciate some help figuring out what I broke on windows/mingw!  I've left the b14 binaries for both linux and windows online.

Source and binaries are in the usual spots:

  ChangeLog:  https://github.com/dave-andersen/fastrie/blob/master/ChangeLog
  Source:  https://github.com/dave-andersen/fastrie
  Binaries:  http://www.cs.cmu.edu/~dga/crypto/ric/

The basic summary of the below:  It uses a lot less memory and is about 15% faster on most platforms.  Single-core machines will be unchanged, and on huge machines (64 core) you'll want to run multiple copies, one per processor slot, for best performance.  But for most of us on single or dual CPU platforms with 4-24 cores, this should produce a nice speedup.  As always, test for yourself.

b15 (2013-04-26)
   - Major internal architectural overhaul.  Sieving and
   primality testing are now divided among all threads
   instead of having each do a single operation.

   The current consequence of this is a good speedup on
   modest-core architectures while using substantially less
   memory.  4-16 core machines should be particularly happy with
   this upgrade.

   Sieves can now be up to -s 4100000000 (4 billion) in size, though
   this does not appear to be a particularly useful setting from
   a performance perspective.

   Single-core machines may suffer a 5-10% slowdown.  If this is
   prohibitive, let me know, but for now I plan to let it stay
   that way.

   Very large, slow core machines (e.g., 64 core AMD) are running
   MUCH slower.  Please either continue to use b14 or run multiple
   copies of the miner, one per physical CPU, using taskset.

   Windows users must use at least Vista (2006, NT 6.0) or later.  XP and
   Windows Server 2003 are no longer supported.