I bought a pair of Boaston Acoustics BA735USB speakers for my i-Opener and tried them as I have two sets of the BA635 and they sound great (the regular BA635's)
The sound was EXCELLANT but the the preformance was disappointing on the Boston USB 735's as the MP3's would cut out and stutter. I improved this greatly by putting in a Kingston Turbochip 400 upgrade, but still Windows media player would still cut out and to get a good playback I had to use a no frills MP3 player I found on the net.
The USB sound card interface for the speakers is too much for the stock IO CpU, I ended up selling them back on eBay for more money that I payed for them.... B-Grn :)
I would think that the BA735 USB's would be great on a 500mhz or faster computer, the IO just doesn't "hack" it!!
FYI also, you can't buy the BA735 USB except from Gateway with a new PC as they are strictly OEM and very rare even on eBay and if you want a pair of outstanding regular speakers get a set of the BA635's or better THEY ARE AWESOME!!