My N900 has been overclocked since 2 weeks after i got it, and that was about 2010_10, and i have never had any problems, in the last few months i had been running ideal 600-900 and even at that speed it felt sluggish at times, so last night i set it to LV 250-1150, and damm it feels like it is on steroids, everything is just flying.

Running Power 49 only
kernel config:
load LV
limits 250 1150
no extra settings.