On Wed, Nov 18, 2009 at 9:13 PM, King InuYasha <ngompa13@xxxxxxxxx> wrote: > Except, that could be false advertising. In most cases, where CPU > computation is not used heavily, 64-bit is actually SLOWER than the 32-bit > counterpart. Optimizations are narrowing the gap, but it still remains > true. You might want to try restating that, because what you're saying sounds like "In cases where the CPU isn't used, 32bit is faster". Which isn't sensible. What I think you're intending to say that x86_64 is only faster on small tight pure-compute kernels like data compression or image processing, but I don't believe that is correct anymore. The biggest gaps I encounter in x86_64 performance anymore tend to be due to things like missing optimizations in glibc. x86_64 supporting 64bit registers is really only a small aspect of the enhancements. Other important improvements include SSE2 as a mandatory architectural feature (as well as a number of other things, like cmov), support for larger processes, improvements to syscall entry, and a doubling of the registers (also sse registers). The last of these is very important because x86 has historically been very register starved and x86_64 makes it basically reasonable. The primary downside of x86_64 is that the larger pointers increase memory usage. You might expect to see some loss in performance from increased cache footprint, but I don't on the multi-megabyte caches on the desktop CPUs. Suggest a benchmark. Now— On a memory starved system. Thats another matter entirely, you have my full agreement that 32bit installs are better off if the alternative is 64bits and swapping. :) -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
