rgturner
I read somewhere that HD Video is okay. HD Audio is not. Is this true?
If anything, it's the other way around, although by and large it's not something you need to worry about.
High-resolution video is more compute-intensive, and you want your computer's resources to focus on audio. However, modern video adapters have their own processor, called the GPU, which handles the most demanding operations so your CPU doesn't have to. Still, it can be beneficial to turn off some video acceleration features in your DAW. For one thing, some audio plugins offload some of their processing to the GPU (e.g. Waves, FabFilter, Meldaproduction).
HD Audio just means studio-quality sound. It means the interface and driver can support 16- and 32-bit data, as well as multiple channels/data streams. If you're using the audio interface that came built-in to your computer's motherboard, HD Audio is both the default and the best choice.
If you're bypassing the integrated audio, though, and using a dedicated internal or external "prosumer" interface, then "HD" is the norm and usually just called "audio". Some DAW users will disable the internal audio interface because they don't need it (and doing so can avoid some uncommon problems). However, having it enabled is usually not a problem.
Bottom line: don't sweat it unless you're having serious issues with audio performance.