From: Jasjeet Singh Sekhon > > > This would be true of 64-bit builds of R, not 64-bit CPUs. [...] > > This doesn't mean that a 32-bit build of R on a 64-bit > processor will be > > slower than a 32-bit build of R on a 32-bit processor. > > There is the issue, however, of running a 32bit application > on a 64bit OS. Under RedHat and SuSE this works > transparently and I've not noticed a performance issue, but > under Debian's or Ubuntu's chroot setup there is in my > experience a measurable performance hit. Of course, one > could simply run 32bit Debian along with 32bit R on an Opteron.
It's my recollection that about a year ago there was still fierce debate about Debian on x86_64: One group got a pure 64-bit version to a usable state sooner than another group that was trying to make a standard conforming version that would run both 64- and 32-bit apps transparently. I don't know how that was resolved in the end, but that basically was enough for me to steer clear of any Debian-based distro for x86_64. Andy > Cheers, > Jas. > > ======================================= > Jasjeet S. Sekhon > > Associate Professor > Travers Department of Political Science > Survey Research Center > UC Berkeley > > http://sekhon.berkeley.edu/ > V: 510-642-9974 F: 617-507-5524 > ======================================= > > > > Thomas Lumley writes: > > On Wed, 5 Apr 2006, Jasjeet Singh Sekhon wrote: > > > > > > > > Hi, > > > > > > 64bit CPUs, such as opterons, help significantly with > large databases > > or if you are running multiple > processes. But there is a speed > > penalty if you are not. > > > This would be true of 64-bit builds of R, not 64-bit CPUs. > > > > On a 64-bit processor you can usually run either 64-bit or > 32-bit builds > > of R, and the 64-bit one will be able to access more > memory but will be > > slower. > > > > This doesn't mean that a 32-bit build of R on a 64-bit > processor will be > > slower than a 32-bit build of R on a 32-bit processor. > > > > -thomas > > > > Thomas Lumley Assoc. Professor, Biostatistics > > [EMAIL PROTECTED] University of Washington, Seattle > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
