I got N900 for little over 2 years, no problems..everything is great, until one day it decided it will start lagging so I re-flashed, everything is great, I installed Power Kernel, after 7 days phone bricked..I never saw that overclock is better, Conky is saying I play only to 600MHz..

So I re-flashed again everything is cool, phone working after 2 month no overclocking again lagging so I re-flashed again, installed CSSU, now every time I turn on facebook chat and web browser it's lagging, if I open more than 5 windows it's freezing..
So I wanted to overclock, but again Conky register only 600MHz, using CPU tweek..

Does anyone has problems like me with the phone?
It's acting like it's dieing..so annoying..anything I turn on can push processor to full, even Faster app mng and therminal in same time, turned on is freezing my phone..
Is it dieing signals?
Anyone with similar problems?
Any solution or to buy new phone?