maybe the network card driver is crazy.
doing some pointless thing all over again and again.
if you run "top" in a terminal, can you see an offending process using 100% of a core?
does disabling in BIOS, or removing the network card/interface/stick, "solve" the problem?
if not, this is deep.
a reason for your computer working with awesome may be, if no network manager is launched, then none of the crazyness happens.
you may try disabling the networking manager in gnome/KDE, preventing it from being launched or even removing try ; try to use wicd instead.
when I install a desktop that only gets network from cabled internet, I get rid of the network manager and use a simple /etc/network/interfaces file. old text and CLI but that gives me one less thing to worry about.
btw, I awesome is a good choice for tiling manager I'll have to try it
. there are so many ones. I may judge it given the names, most are non-descriptive but there's "awesome" and "ratpoison", surely the former will be easier than the latter