25.05.2011, 21:13, "Andrew Haley" <aph@xxxxxxxxxx>: > On 05/25/2011 12:58 PM, Bill Davidsen wrote: > >> Chris Adams wrote: >>> Once upon a time, Fernando Cassia<fcassia@xxxxxxxxx>; said: >>>> Well guess what? 64 bit code is bigger (bigger pointers) and thus >>>> slower, because CPU cache is less effective, with bigger code. >>> All other things being equal, that might be true. However, all other >>> things are NOT equal; pointer size is not the only different between >>> i686 and x86_64. The biggest gain is that x86_64 has a much larger >>> register set, so a lot of things don't have to hit RAM at all (and are >>>> much faster). > > Also, the ABI is much better, and this may be almost as significant. > >> Unfortunately that biggest gain only occurs if the program logic is such that >> registers run out often. > > Which, in the case of gcc-generated code, is most of the time. gcc > was originally written for, and still works best with, a machine with > 16 or more general-purpose registers. 32- bit x86 only has five or > six registers to play with, and this just isn't enough for good code > generation. I don't think that Java has it very much easier. I have been running x86_64 since Fedora 10, but had issues with 3rd party games that refused to run (with all the 32-bit libraries in place). So, going for all-32-bit with Fedora 15. I have 2 gigs of RAM. With more than 4 gigs the x86_64 is the only to go. -- Best regards, Misha Shnurapet, Fedora Project Contributor https://fedoraproject.org/wiki/Shnurapet shnurapet AT fedoraproject.org, GPG: 00217306 -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
