I know and did not mean that at all.

For GUI, it is good for dummy like me. But I remembered using one called Memorybooster or something in my old Symbian N95. The app could free up some 0.1 or 0.2 MB of the precious 56MB RAM in the N95, but it always occupied about 3 or 4MB if you run it or not due to the GUI thing. I uninstalled it right after the first try.

Edit:

I installed the Titan kernel (power46) again yesterday, cannot resist the temptation longer

My N900 can only work normally either at LV 250 850 or ULV 250 600 - 750, otherwise it just reboots itself after a few clicks. So I cannot default it to IDEAL 500 900 like you require. Maybe I will default it to ULV 250 750 after several days of testing, it seems to be stable now.

Iptable iproute intalled, works like charm, much better internet surfing, haven't found any side-effect, but cannot test. That is to say I have set my wireless connection to maximum power saving with WLAN transmission power 10mW.

How can I install your other scripts? Is there any easier way for dummy?
And how do I uninstall them in case problems occur?