Date: Fri, 12 Mar 2004 14:44:14 -0500 From: Jem Matzan <valour@thejemreport.com> To: freebsd-amd64@freebsd.org Subject: Re: Peer review of AMD64/FreeBSD article Message-ID: <4052130E.9060601@thejemreport.com> In-Reply-To: <20040312174736.GD7661@Odin.AC.HMC.Edu> References: <200403121301.i2CD1oQC076505@lurza.secnetix.de> <4051B7D3.8020404@thejemreport.com> <20040312174736.GD7661@Odin.AC.HMC.Edu>
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Brooks Davis wrote: >On Fri, Mar 12, 2004 at 08:14:59AM -0500, Jem Matzan wrote: > > >>Hyper-Threading seemed to help with processes that didn't require a >>heavy CPU load. The OpenSSL tests show it being markedly faster in the >>smaller algorithms, but lagging way behind the 64-bit Athlon64 when the >>serious number crunching comes into play. Intel's press kit shows HT >>(and SSE3) giving an advantage when multitasking with four desktop >>programs in Windows XP. It's just too hard to show that reliably though. >>There's a lot of anecdotal evidence to suggest that AMD64 is faster on >>the desktop (in X) in 64-bit mode than the Prescott is in 32-bit, but >>I'm having trouble proving it. >> >> > >I think it would be a mistake to assume the HT is what accounts for >the performance difference. There are so many other architectural >differences it's hard to see how you could isolate the effects of >HT. My suspicition is that better performance on small >algorithms is due to them being more or less memory bound (and thus >similar to the pure synthetic benchmarks). > >-- Brooks > > > By comparing the Pentium4 to the Athlon64 in i386 mode, you can better see the advantage of HT Technology. This is especially evident in the OpenSSL tests. -Jem
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