On Mon, 2009-12-07 at 09:44 -0700, Greg Woods wrote: > On Mon, 2009-12-07 at 16:18 +0100, Joerg Bergmann wrote: > > The problem of the Pentium 4 D: It is not really a dual core one. > > Hyper-Threading means: There is one core with two execution paths, which > > means some of the common CPU features, but not all, are present twice. > > One feature in particular that is not present twice is some of the > caching. This is sort of why they named it "hyperthreading". If you can > get multiple threads of the same process, sharing the same memory, to > run simultaneously, there is a performance boost. But if you try to run > two completely different processes simultaneously, there will actually > be a performance LOSS because of all the cache misses this will cause. This may not be true - in the high performance computing community hyperthreading is usually not used, since if you're cpu bound, then execution is about 20% faster in without hyperthreading since no performance is lost because of the dual core emulation. However, in normal desktop use you don't really care about the MFLOPS; hyperthreading makes the system more responsive. -- Jussi Lehtola Fedora Project Contributor jussilehtola@xxxxxxxxxxxxxxxxx -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
