I'm running Amarok on an old-ish desktop and interested in knowing if anyone can suggest tricks to optimize its playback, mainly avoiding periodic hiccups in playback due to CPU or other resource conflict.  Using an Athlon XP 1800+ CPU.  CPU consumption hovers around 65-75% when running Amarok & upsampling in ALSA.  I'm experimenting with using Nice to increase the priority of Amarok above default and that has helped.  Does Amarok use /tmp or some other temporary storage that I could redirect to RAM disk?  Any network optimizations (I'm pulling FLAC files from a remote machine on a local network) been tried?

I'd suggest turning off upsampling for starters, to see if that makes any difference to performance. It shouldn't make a hell of a lot of difference to sound quality and might also be your problem with not getting gapless flac playback. My old machine was an XP1800+ with 512MB RAM, and Amarok was only using around 5% cpu most of the time, with a very brief spike on song change.