I am having the same issue, however, I do not have a time capsule, but just a simple internal drive networked (via a windows workgroup) that is sharing the music. I load the music (via wifi, or ethernet) and all goes fine, except processing album artwork, or determing gapless playback, takes FOREVER....as in I let this run for two straight days, and still it did not finish. Any help would be GREATLY appreciated, BTW, I am running a BRAND NEW Macbook Pro, I5, and I get this issue, ONLY with that machine. When I try the same exact scenario with my POS Dell Inspiron 8600 (windows xp - PENTIUM 4!) I HAVE NO ISSUES, even on wifi, gapless, and album artwork, Zip right through....on a library with 160GB of music......and BTW.......
Just because someone has a large music library does not mean they are a pirate, I happen to collect and encode VINYL (of which I have over 1000 lps), I use them for DJ mixing, I also am a musician and have been collecting music for 25 years! I never toss anything, I archive it. I also have about 30gbs of stuff that is MY OWN COPYRIGHT WRITTEN MUSIC!!!! That is over 1000 tracks right there, just from live shows, recordings, and other scratch ideas.....
Also, I have a wife, and (being a musician & DJ) I have probably gotten more P@$$Y than most people on this site. My Wife understands completely why I do what I do, she does not think its sad, especially since a lot of my time has been rewarded with you know....A PAYCHECK......so just because you are a SAD person, and you might know a bunch of other SAD people (like ones who condemn people on chat boards) Does not mean we all are.