i have the exact same problem and put in a ticket.
I got a response, and they essentially looked at my logs and changed something in the config? I guess. Here was what I got back -
"I went through your logs and (maybe) did something to fix it. I found that we were hooking into your Realtek Audio GUI program, which may have had a part in this.
Try it out again and let me know if it is any better?"
It is not better. Still about 15 seconds off.
I have a r9 280x, Windows 10 as well. I use the realtek Audio drivers with my Mobo, which is a ASUS Impact VII. I may try and uninstall the Drivers and run stock audio.