my personal opinion of why 'some' phones can 2.2 and some cant is this.. (just guessing here)
when these cpu's and other parts are made in the giant machine that makes them, im assuming they are not 100% accurate 100% of the time, so maybe 2 identicle cpu's can still be different in a sense of maybe more thermal compound was placed on 1 than the other or more saulder etc.. so 1 cpu may have more strong points than the next.. so when we OC these things, one may have a better/stronger connection than the other.. so one can handle it but the other cant.. just cant handle the requested frequency so it craps out and reboots lol
as for the seeder tweak.. again this is in my own opinion.. i think it DOES help, but i think it's honestly meant for people who actually OC lol
from my personal experience with it, my device did seem to have less lag as a 'whole' BUT!!!! if i were to try multi-tasking, then i would notice small glitches between each task
ie: i use power amp, 90% of the time im playing music in the background, so when i have the music playing, then lets say i decide to open up gallery.apk, the song will glitch out for a second while opening the app... this NEVER happened prior to using the seeder tweak...
but i feel maybe if i was running at 1.2, than maybe that wouldn't have happenned... im not sure, and i didn't care enough to find out... here are my reasons!! lol
1: I dont need it... device always ran fine without it
2: I never OC, well used to (untill i discovered that GTA Vice City was released) now i go to 1.3 when i play that game
LOL
but all-in-all it's one of those things that is just 'user-prefference'
EDIT: to help you understand my point of view, I am a strong believer that EVERYTHING you do on a device, uses RAM!!!
same as a PC, if you fart while skimming through google search results, it uses RAM!! lol