Root Memory question

[Peter123]

I am using Android System Info app (requires root) to monitor the phone performance and memory. I have a rooted stock 2.1 OTA with the July RUU.

Right now Android System Info says :
Internal memory: 110 Mb free
RAM: 49 mb free

The interesting thing is that when I reboot the phone and and check the memory with this app it starts out with free RAM of about 80 Mb.
Then the free RAM space starts shrinking on its own without any phone activity (from me) and in a few hours it goes dow to 48 Mb (25%) and later as low as 29 Mb.

As I know RAM is used by active programs and services.
When I look at the running programs and services I see:
Android system 40,2 Mb
HTC sense 32.7 Mb
android process acore 26.7 Mb
Dialer 29.8 Mb
Gmail 26.3 Mb
Android system info 25.9 Mb
com.Google.processg.apps 23.4 Mb
Calenadar 23.4 Mb
...
As far as CPU usage is concerned:
Androis system info 14-17%
Androis system: ~14-2%
Swype
Bluetooth share
...
The CPU usage numbers are jumping around widely as the mutitaking system juggles the tasks.
Intersetingly:
Androis system info is alway has the highest CPU usage.
Bluetooth share is also running and eating up memory although the bluetooth is turned off.

Anyone can comment with a few words on Eris' memory management?
peter