For anyone interested in optimizing their Windows-based (HT)PC music source I wholeheartedly recommend downloading the free(!) "Fidelizer" program via below link(download option at the bottom of the page):

In short Fidelizer optimizes/economizes the environment on your (HT)PC, which can be done in three stages by shutting down processes not important to anything other than (roughly) the most basic needs with regard to A/V playback. As it says on their homepage:

Fidelizer has 3 optimization levels. They're all for the same goal to sonic improvements. I'll leave them all to your judge whether they're subtle or big difference. At any rate, you should leave your ears with it for at least week if it doesn't hurt your computer. Some people need time to adapt to changes.

The first ones is 'Professional'. This will optimize system to the extend that it won't significantly affect overall system performance. You can work as usual while enjoying improved multimedia experiences.

The next ones is 'Audiophile'. This is quite dedicated ones for those who pursue higher fidelity. It will lower system/network performance so audio can gain more priority to access to resources at time. It will also lower most processes including system ones to lowest level so you need to close your audiophile player before using it.

The last ones is 'Extremist'. As the name say, this isn't risk-free feature to try. It will stop most bundled system services leaving only important ones for audio. Yes, it will stop network services and such too. You may not know but Windows Audio and DHCP share the same process in service host provider so disabling network can significantly improve sonic performance. I also add some options to keep network and user experiences (HID,Tablet,Themes) working for some applications.

For general use, you should stick with 'Professional' level but computer in today's market should be able to use 'Audiophile' without hassle about system/network performance. I use 'Audiophile' level on AMD Phenom X2 550 BE machine and ended up running fine for 24/7 usage.....ya it's old and cheap unlike i7 or Athlon II X6 but it still works.

I'm using the 'Audiophile' level myself, and have experienced no problems at all nor any noticable limitations in the use of my HTPC. One of the people who was lead to Fidelizer via my initial recommendation(I stumbled upon Fidelizer from a recommmendation over at the JRiver forum) is a software programmer himself, and he's successfully tested Fidelizer quite thoroughly to see whether any glitches should occur that might be detrimental to the overall funcionality of the PC. As it's stated on the homepage any "newer"(even over 5 years, I suppose) computer shouldn't experience problems with the use of Fidelizer.

Taking up only 272kb Fidelizer has provided a noticable sound quality improvement not only in my setup, but also in all the setups of the audio-friends of mine to whom I've recommended the download. One of them even goes to say he's hardly heard a more substantial sonic upgrade in a long while(to which I definately agree), and with this in mind think about the following: Fidelizer is FREE!

Indeed I'm perplexed that this little wonder of a free program hasn't received more attention among the computer audiophiles, at least what I know of, and I certainly don't see any reason going about hiding its presence.

So, without much further ado: go ahead and download Fidelizer ASAP. Any questions, be they with regard to download/use or anything else, are welcomed.
Version 3.0 is released.
Fidelizer installed , admittedly improvement in sound but one thing that I loose control with JRemote in "Audiophile" mode is most inconvenient , hope network not affected if possible in the first 2 modes
How does one know Fidelizer is running, or is that the point of Dtc's comment - it doesn't show?

When I disabled JPlay (trial) and installed Fidelizer and rebooted, Win 8 Action Center shows a problem with Cygwin. Which of these two is that attached to?
Fidelizer doesn't 'run' anymore than your auto mechanic 'runs'. What it does is shut off or lower system priority for processes that aren't needed for audio. It hot rods your system temporarily for audio then puts it back where it started when you reboot. I always see the security icons complaining during this phase as Fidelizer retunes. I generally use Fidelizer in extremist mode as disabling network makes a significant improvement...the other stages don't make that much of a difference with Jplay 5.1 in Xstream mode
The simple answer to my question (Davide256), something I hadn't noticed, is that the user has to start fidelizer manually each time, and reboot to get rid of it.

Now, being aware of that, there are a bunch of problems:

1) fidelizer kills foobar2000's volume control (Windows Sound Mixer is not an efficient way to conrol volume on the fly, to say the least);

2) How can one A-B or A-B-C (with JPlay or another player)?

a) it takes a minimum 45-60 seconds to turn off whatever else is on, if anything, and fidelizer in Pro mode, get their website opening out of the way, and then go back to the player and start the music (in Audiophile mode, fidelizer's install just ran on and on, except when JPlay had been part of startup, then stopped);

b) since fidelizer kills the player's volume control, time has to be spent adjusting (Window's) Sound Mixer, hoping to get close from memory;

c) since fidelizer does not show in processes or services, doing more than one comparison requires reboot and starting all over again (~2-3 minutes minimum?);

Under these conditions, I sense a difference with non-fidelizer vs. fidelizer, but it's hard to tell for sure or exactly what it is. Likewise, with JPlay (trial) vs. fidelizer, I sense that JPlay is more "atmospheric" than fidelizer, while fidelizer's tone or pitch is lower (something bothering me about JPlay is with its increased atmospherics, it also seems to raise the tone about "1/3" octave).