Quibble: Intel core i5 machine: install 32-bit linux and intel fortran or 64-bit?
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From: Carlie Coats on 8 Feb 2010 10:22 Tim Prince wrote: > On 2/7/2010 4:38 PM, News user wrote: > >> So, is there any difference in the computation speed between the 32- >> bit or 64-bit? >> If not, for me it is easier to use the 32-bit software (linux/intel >> fortran) since I also have >> older 32-bit machines. > > Assuming you don't write anything big enough to take advantage of the > larger 64-bit addressing space, the answer is application dependent. > Sometimes, compilers will perform more optimizations for 64-bit mode, on > account of less tight space requirements, as well as the large number of > registers available... Our experience is that the extra registers/opcodes etc have a significant (>10%) effect on the kind of scientific (environmental- modeling) codes run by my group. Additionally, extra RAM for I/O buffering may speed up processes significantly: some benchmarks we've run show a 20% speedup going from 8GB RAM to 32GB on an 8-core machine -- and that for a meteorology model with a working set of only 1.6 GB, *far* under either RAM size. -- Carlie Coats |