Nothing. That's perfectly normal.

I lift this thread as I'm still confused what is a normal ram usage. Does this look normal?

http://img683.imageshack.us/img683/2641/ramuse.jpg

Only apps I've installed are 2g/3g selector, rootsh and OpenSSH client. Still ram usage jumps to that in a five minutes of reboot.

The memory manager for the device is pretty optimal at figuring out how to optimize things. If you feel the device is being slow, look at what you have running/loaded and see if you can spare it. (Widgets on your desktop, background programs, tool bar plugins, etc.)

Since there's no way to upgrade the amount of ram in the system, worrying about how it's being managed is kind of pointless. And if you haven't loaded it up with 50+ running apps or widgets or plugins, you're pretty much good.

Actually I was looking for reasons for short standby battery life (~30 hours), never had any problems device being slow with any programs

But does ram usage affect on that, if cpu usage stays around 0-3 % all the time?

Dynamic RAM (DRAM) like we have in these devices consumes power whether it is in use or not (for most definitions of 'in use'). So, the amount of RAM provided is subject to a tradeoff against battery life.

Linux prefers to use RAM for disk/file caching than to leave it unused, as unused RAM is a waste of space and power (and RAM). Swapping to/from the eMMC might consume more power though, not sure, but if you're idling at 3%, then you're probably not swapping.