We're happy to announce that Gromacs 3.3 has been officially released on Tue Oct 11 16:16:51 CEST 2005

There are a bunch of new features that will hopefully be useful. A  more or less complete revision list is available online, but just to mention a few highlights:

• Assembly loops for x86-64, both single-and double precision.
• (retuned from the first betas, works on EM64t too)
• Assembly loops for ia64, both single and double precision.
• TIP4P-specific optimization in all assembly loops, using the "normal" atom order.
• PME scales better
• Support for FFTW2, FFTW3, Intel MKL, and built-in FFTPACK fourier transforms
• PME is slightly faster, and scales better
• Free energy support in PME
• Replica exchange
• Much faster normal mode calculation, which works for huge systems too.
• Random access in XTC trajectories
• QM/MM support

You can find the source tarball under the download button, and also binary packages for Linux/i386, Linux/ 
x86_64, Linux/ia64, Linux/ppc64, and Mac OS X.

Have fun, and report bugs with the new tracker 
http://bugzilla.gromacs.org !