Windows 7: realtek: 5.1 & 96/24

When I set default format to 96/24, I get horrible lag in addition to distortion when playing a stereo@44.1/16 wav file of classical music in vlc / windows media. When lowered to 96/16, there is no more lag but there are still clicks, which are also present at stereo@96/24 and quadraphonic@96/24.

Flash 10, on the other hand, plays death metal without any distortion or lag at 5.1@96/24.

It works at 48/24 though, but I would like the default to be 96/24. Not going to happen?

Also, will 96/24 be properly functional if used in exclusive mode via ASIO? The higher sampling rate means that there's less distortion resulting from time / pitch bending. And 192/24 is simply unnecessary.

My audio chip is Realtek ALC888s.
However, my 5.1 system is cheap enough to not have SPDIF input. Analog (green/orange/black) tests just fine.

Update: my power supply is pretty shoddy (12.34V on 12V with multimeter, 5.09V on 5V with multimeter). How much of a contributing factor is that?