Hmm. I have an (older) laptop, and when running Win10 64-bit, if you increase the RAM to max capacity for that laptop's mobo, 2x2GB, the audio fails in Windows. No sound! You have to go into selective startup, and "Limit Max RAM" to 3GB, if more than 3GB is physically present. Weird, huh?
Edit: Try setting "Above 4G Decode" to "Enabled", and see if that works at all to fix it. (I think that this laptop lacks that feature.)