Memory usage

[normal]

I just installed kde 2.1 on my Potato desktop, but it seems to run slowly.  
It's a 300 mhz celeron, so I don't expect it to be too fast, but under Memory 
in the control center it reports 125 of the total physical 128 mb of ram 
being used, even when no applications are open.  If I open konquerer of some 
other memory-intensive app the numbers fluctuates up and down a little bit.  
What's going on?  Is it supposed to be like this?