6+ year old pc/os. should i upgrade?

You did not mention the player program you were using on your PC, and yes it does make a difference. I run Mac,but I hear that J River and XX High End are the players of choice.

With that said, a dedicated music server is best. You can strip it down of other functions to keep it clean. Considering your other equipment, I'd highly recommend buying a standalone computer. I'd recommend a tricked out Mac Mini. Put another way, it would most likely make a bigger difference in your rig than any one of your cables as a lower cost.

I have a 6 yr old PC running an older version of Fedora Linux that is my dedicated music server. It's performed flawlessly, and I feel no need to replace it anytime soon.

If your old machine works fine and you really don't want to spend the money on a new one, then it's not completely necessary to upgrade.

Michael

Linux and Vista are two different things. IIRC, XP or 7 are the preferred OSs. Please correct me if I am wrong.

USB connections have gotten better. Faster & you get more of them.
Wireless has improved considerably.
Vista is a dog.
Media player has improved considerably.
Most new PC's will have internal drives big enough to back up your 1TB, which is a smart thing.
Burning new cd's will be much faster and cleaner.
Power supplies usually fail after 5 years.

You are using a $49 pc with a Perfect Wave. Would you use $49 speaker cable with $5000 speakers? I hope not.

Can you describe the computer system a little further (make, model, etc.)? I assume you are talking about a desktop machine, since you mention the sound card and video card. But a P4-1.8GHz cpu in a desktop machine sounds to me like something that would date back about 9 years or so, while Vista was only introduced a little over 4 years ago.

Did you update the machine's original os from XP to Vista? If so, have you seen any performance issues? If not, then I agree with Michael that there is no reason to upgrade, at least until you spend some time trying it with the Perfect Wave. But I would be surprised if an 8 or 9 year old machine with a 1.8GHz cpu could do a good job of handling Vista.

Also, is the 1TB hdd installed as a second hard drive (highly preferable), or is it serving as the main "c" drive, on which Windows and program files are located (which is definitely not preferable, especially in a marginal computer)?

Regards,
-- Al