Author: Anthony Cozzie
Date: 11:09:35 08/13/04
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On August 13, 2004 at 12:44:21, Aaron Gordon wrote: >On August 13, 2004 at 11:55:12, Anthony Cozzie wrote: > >>On August 13, 2004 at 02:12:04, Aaron Gordon wrote: >> >>>All the bad press finally got him redo the review. I told'em a few cflags he >>>could use to make performance better.. unfortunately he didn't do the PGO >>>optimization. I think he thought because I said I used GCC 3.4.1 that it was >>>only available in 3.4.1, who knows.. >>> >>>Anyway, looks like the 64bit stuff on the Nacona offers no performance benefit >>>(only addressing). Would fit with the rumors I heard a few months back. We'll >>>see I guess. Supposedly they just "got it working" for now and will fix the >>>performance issue later. >>> >>>Anyone know any hard facts about the 64bit Xeon stuff? Broken? >> >>I thought Nocona was an implementation of of AMD64 ? >> >>anthony > >From what I hear it is, however supposedly it only has the addressing of a 64bit >chip (ie. can use that much ram, can use 64bit integers/fp/etc), but cannot do >them as fast as it is suppose to be. The way I heard it described was like it >was using the 32bit registers to do all of the stuff.. similar to a regular P4 >trying to do a __int64, long long, or double. > >I can't verify this, but from the results that Anandtech did it sure looks like >the rumor may be true. The other part of the rumor was that Intel was going to >fix it soon. I think this was a quick add-on after they saw x86-64 was the next >big thing and didn't have time to rework the core to get it functioning 100%. > >I guess we'll see in the months ahead... Hmm, that would definitely be possible. And _something_ is wrong with the Crafty benchmark because in 32 bit mode the opteron is not _that_ much faster than the P4 for Crafty. anthony
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