My adviser has a Mac notebook that he bought 6 months ago, and I have a PC notebook I bought a month ago. Here are the respective specs, as far as I know them:
His: Mac OSX 1 GB DDR2 RAM Intel Core Duo, 2 GHz (2MB cache per core) Unknown HD Mine Windows Vista Home Premium 32bit 2 GB DDR2 RAM Intel Core 2 Duo, 2 GHz (4MB cache) 5400 RPM Hard Drive We are both running R. As a test to see whose laptop was faster, we decided to invert large random matrices. In R language, it looks like this: N=2000 A=rnorm(N^2) A=matrix(A,ncol=N) solve(A) This creates a matrix of 4,000,000 random normal deviates and inverts it. His computer takes about 7 seconds, while mine takes about 14. Why the difference? I have several working hypotheses, and it would be interesting to see what you guys think. 1. R on Mac was compiled with optimizations for the CPU, with R for Windows was not. I could test this by compiling R with the Intel compiler, or GCC with optimizations, and seeing if I get a significant speed boost. 2. His R is 64 bit, while mine is for 32 bit windows. (I'm not sure how much of a diference that makes, or whether OSX is 64 bit.) 3. Data is getting swapped to the hard drive, and my hard drive is slower than his. I chose a slower hard drive to get bigger capacity for the price. This is not intended to be an OMG MACOS = TEH R0X0R thread. I'm just trying to explain the discrepency. Thanks! ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
