i dont know if this will help anyone or not but this is my set up. I have the xbox behind 3 surge protections and i cut the power to it EVERY day and have not had one single clock issue. I think whats being forgotten here is that this is a "homebrew" system (excellent hombrew at that) and like any progam used it may have a bug here and there. Example: my buddy justins box-- Ive had to reflash the bios (upgrade) to get it to run certain games (this was mainly a PAL NTSC issue though). There have been times when copying a game when someone runs through the house causing vibration, in turn causing corruption in the copy. Try a re-copy and it works fine.
Dirty dvd lense can also do this (if youd like, i can post a tut on how to clean it easily, anyone can do it)
I have also had my eithernet card start puking out without any signs other than something working that is now corrupted. (re-ftp'd with same results.) I replaced the card and ftp'd and boom, it works.
Like i said, i dont know if this helps anyone, but it could be as simple as upgrading your Evox.