Memory hole/leak in RH9?

I've been running RH9 for a little over a week now, using it as a file and web development server. It is on a Pentium III 500 MHz machine with 768 MB of memory. Immediately after booting up, memory useage is around 50%. The problem is that within a few hours after bootup, the memory usage has crept up to 100% and remains there indefinitely. No apps have been opened, and the only things running are what I need -- Samba and Apache web server. I only installed the packages I needed, and I went through the Services settings panel to make sure there wasn't extra crap running in the background.

The machine doesn't get heavy use--there's only four people that ever access it, and that's only via networked drives to play music and simple stuff like that, and that's not even very often. I use it to test PHP pages I develop, and that's it. The memory it has is more than adequate for what it does.

This is becoming an issue because when the memory usage is at 100%, there is a lag when serving web pages. If anyone has any ideas, please let me know. Thanks!

All of your memory being used in Linux is normal. It will store cache and what not in there from services running already, etc.

The only time you should worry is when your swap becomes used up, your system starts thrashing and such. Or your cpu or load averages becomes too un-normally high, etc.

If your seeing lag in your responses or system, could be a problem with your memory or system as a whole. Have you ever had any other OS installed on this machine? And if so, did it do the same thing or run fine? Which OS if so?

Prior to the current installation of RH9, I was running Windows 2000 server and then Windows Server 2003 for a few months, and they worked normally. The lag time is not horrible, just not as quick as it is when the memory is not full. I can live with it. Thanks for clearing that up. I'll keep an eye on the swap file for now.