Yep...I think there are two options here. 1) Your system isn't going to pick up the differences and a MB isn't going to do much to change that. So, you can either chill with the 4490 and be happy or plan to spend significantly more money to find something that will have a real impact. And even if you do spend a ton of money, it's still no guarantee... 2) You're a little bit DAC-deaf. This would be FANTASTIC news. Spare your wallet, sit back, and enjoy the tunes.