I was doing some searching it seems to be the exact issue as in this thread regarding the backlight:
I haven't tried the beta drivers, however it looks like it may be solved with those?
Do the beta drivers work with windows 8? Or should I just wait until 8.1 is released?
This issue is being handled by Diego_Intel in this thread:
My best recommendation is to follow up in that thread. As per your question Win 8 and Win 8.1 have a similar platform but not the same one so you can try installing the Win 8 drivers at the moment while we come up with the Win 8.1 drivers.