Seems my issue is common, i've downgraded my network driver to the vista/7 driver to see if that helps.
Windows 8 - PC Gaming Issue - LAG Spikes
Windows 8 PC Gaming Lag Spikes - Neowin Forums - Page 3
Apparently nothing works, i think it's because my video card doens't have any integrated ram and w8 + LoL simply use too much of my 2gigs, i've had similar lag back when i used w7 and my laptop would overheat, but that isn't the case now. I've found a student edition of win xp and i'm going to try playing LoL on that.