I saw the threads about Fidelizer and tried it with my PWD II and Bridge. First I installed it on my Windows 7 laptop that runs either jRiver or eLyric. I tried jRiver first with the Professional setting. Wow, what a difference. The soundstage became more solid, the images firmed up and stayed in place. Bass notes were better defined. An overall improvement. As eLyric sounds better I soon switched to it. The sound became even better there. The only downside being with eLyric it really slowed down the album art display on my iPad.
Next I installed Fidelizer Professional on my WHS as well. There was easily 2 times the difference.
Then restarted both computers and tried the Audiophile settings. This was even better. Certainly on the scale of updating from the PWD to PWD II or more. Easy to hear. The speakers seemed to disappear. The music seemed to slow down, have its own space, become more deliberate. It wasn't as if I knew there was a problem before but I'd call playback without Fidelizer kind of jittery.
I did try the Extremist settings. This did not work for me it closed down the network and did not allow communication between the laptop and WHS. Maybe I'll try other combos latter.
As for Ethernet cables not making a difference, I've found that it clearly does, Cat 6 better than Cat 5, and Cat 7 superior to both. Not huge blow me away differences if you go step to step but certainly worth doing from CAT 5 to Cat 7. I've heard that the new Ethernet cables from Audioquest are CAT 7.
I'd try Fidelizer on any Windows computer. All you have to do is reboot your computer to remove it. And if your PC is restarted you'll have to reinstall Fidelizer each time.
Try it you'll like it.
And it is free.