well the stock launcher is abit sluggish and pretty heavy, it got some glitches. it seems to make the GPU run pretty hard.
Whereas for nova launcher or go launcher, RAM consumption is abit high, but u dont feel the lag, no glitches or stucks between transition, seems to have less heat for normal use. gaming, browsing all unaffected, phone still heats up based on my observation la ~ haha.
if xda comes out with more mods, i wish they can permanently remove lenovo's heavy skin. replace with stock JellyBean skin. lol
for question 2
try this few apps

https://play.google.com/store/apps/details?....danez.cpusaver

https://play.google.com/store/apps/details?...ng.overclocking

i would recommend the 2nd link

u can go search at google. download the paid apk for free 

i also still newbie la 
still learning alot of things

yah. their roms are pretty stable

for k900.. no haha sorry

they had just started to talk about working on x86 architecture with Intel ppl last week i think.
so... not sure what is CM direction.. tablet or phone or maybe even PC

Didn't know this thread is still active. 
Well anyway how's the experience of going through the warranty of the phone with Lenovo warranty center?

RM 800 better just buy a new phone.
I have problem with the phone. It won't charge at all.
I leave it for 2 hours and it only charge up 2%. 

Does your phone shut down when reaching 15% battery level?

guy how this phone battery life ?

Getting my phone tonight.. K900 32GB... feeling excited... =)