You can split HDMI output from an HTPC just fine. The problem is that the HDCP will not work. So while you can clone the desktop and view it, and WMC and possibly any non copy protected material, if you try to watch liveTV or recordedTV, its going to flash up the HDCP error. The other issue you will get is that even if you get it working, your audio is going to go down to the least common demoniator. So if your TV can't handle DTS-MA or TrueHD, you won't get that on the AVR either.