Apache memory consumption

[peters]

Hello, we are using Apache 2.2.15 on Centos6.8 with MPM model (prefork.c) and more or less default configuration.
After 1-2 day usage (20 agents), the memory consumption rises to 2+GB of RAM and start swapping. Is this common behavior, or is some Apache tuning needed?
In case we restart Apache gracefully (while the same agents are connected), the RAM usage of Apache goes down, more than by 1-1,5GB.
What is best practice in this case?
We tried to use Nginx instead, but failed while loading huge tickets with more then 50-70 articles and therefore stayed with Apache.

Thank you
Peter

[jojo]

you should add more RAM to your machine

[peters]

We already have 4GB and it's 32bit machine... Probably need to move to 64bit.