It takes time to get everything right. You need to optimize the computer OS for audio play. Not all computers sound the same. I have a friend that built 2 computers and one of them sounded awful. So you have software and hardware to get right on just the computer side. You also need a good USB converter they are not all created equal. I can tell you in my opinion and with my hardware Windows Server 2012 sounds amazingly better than optimized Win 7.
You should be able to beat the sound of a Sony 5400 as I owned one a couple of years ago.