Running V.5 I encounter sound glitches with any host (Ableton, Reaper, energyxt) using ASIO2 64, just normal stereo playback or VSTIs. When i switch to VSTIM/XTC-Modus there are no problems. I use the same drivers in my XTC-Project and both the XTC and the normal mode have a 64 ulli-latency setting.
Have you tried going into the device manager, ( Right click on computer )and deactivating the onboard sound cards and HDMI devices if you have a newer graphics card with the sound for hdmi, you may have already done this but I tried this earlier on today and there were no glitches in the sound compared to yesterday when I hadn't done this.
Oh and I've come back from the Steinberg forum from too long away and I think I'l keep on putting my Computer setup in my signature.