I believe I have wrote about this before, here and elsewhere. I have 2 monster machines--- master/slave, both 6 core i7-4960x turboed to 4.0Ghz, 64 GB of RAM, SATA 3 SSDs. I've been working with this library for a while now, and I have to concurr with the OP. There's just no way to run a full ensemble of DS without voice dropouts. I've tried every conceivable setting and every conceivable file distribution. Sometimes I can get away with turning off Vel XF, but this is an unacceptable kludge of a workaround. If someone out there is doing it successfully I would love to hear how.
My wish is that VSL would re-save the enembles as single patches, because streaming 8 patches at once to get a single note is just killing the performance of this otherwise great library. Lord knows how people with lesser machines are making out with it. I realize that the power of DS is its ability to vary each solo instrument, but realistically most of the time I'm using either the full ensemble or divisi a2. Just having these two options would be fantastic.
Thanks for your great products!!!
MOH