Alex K, I don't want to undermine what Jos is recommending and doing. We need people like him to continue to make software for our use. Also it is risky to assess what Jos' goals are. In reading his tread I get the distinct impression that he is designing systems for use by hobbyist or home users and not the professional (live & studio).
Older Yamaha soundcards use the 4 mb wavetables. While such wavetables are amazing for their size, the sound quality in terms of today's standard is very low. Latency of Yamaha's soft synths and soundcards are generally very high and not useful for live performance. Yamaha's SW1000XG soundcard (ASIO, WDM) may have overcome some of these problems with their recent drivers but in the past the best latency they could get is around 40 to 50 ms - not good enough!!!
Yes, I get excellent latency (2.9 ms) with software synths, heavy duty streaming from the Hard Disk and professional effects. You need to use the better or pro soundcards, good drivers and good soft synths (Kontakt, Halion, LiveSynth Pro, etc.). I know some find this kind of information hard to accept but it is true!!! The sound developers and serious composers use this equipment and software all the time for live and studio work. In fact, you will find that they will often LAN together one sequencer PC with 2 to 6 sampler PCs with no problems with latency or overall quality of sound. These people use the Vienna Symphonic Library and Eastwest Quantum Leap Orchestra ($3000, 68GB):