On Fri, Feb 24, 2012 at 03:13:07AM +0200, Nikos Chantziaras wrote > The speed gains of building for specific submodels of CPUs might > be there, but they're minimal. Benchmarks have shown (can't find > the article, it was on Phoronix) that after -march=i686 you get > diminishing returns.
In that case, the benchmarks are useless. From my personal experience... a fresh i686 install on a 4 and 1/2 year old Dell with onboard Intel GPU was not able to keep up with the slowest available speed on NHL Gamecenter Live. Ditto for 1080i TV from my HDHomerun tuner box. After rebuilding system+world+kernel with "march=native", it works just fine for the above tasks. I'm not the only one to see this. See thread... "Slow not in sync movie playing with mplayer2, ffmpeg, x264 with intel core i5" starting Sun, 12 Feb 2012 on this list. As I mentioned in that thread > Optimizing one library may seem very minor, but it all adds up when > you optimize every library on your system. To get the full benefit of optimization, you need to optimize your entire system. The i686 code used for the install CD has to be generic lowest-common-denominator i686 code, in order to run on every 6-year-old i686 cpu out there. The tradeoff is that you lose the benefits of optimisation. -- Walter Dnes <waltd...@waltdnes.org>
