I have been using XOOPS on my site for one year. And now i am starting to get into troubles with my servers.
2 months ago i bought a hosting plan from http://www.kazix.com and they had XOOPS pre installed as well.
But as my site started to gather people the hosting company complained that my website was using more server resources than allowed (more than 5% i guess). Finally they had to suspend my account after their server crashed 3 times.

So i moved to http://www.handinhandcomputing.com ( another excellent host) and now they are having the same problem. my site has been using over 50% of their RAM usage on the shared server.
I don't understand why this should be happening. I have already disabled some modules which i bleive may have caused this such as Chess module and XOOPS Avator Maker.
The other module which may cause a problem is Xcgal module which i can't disable at the moment.

Wanted to share this information with you incase if you had not experienced these kind of problems with servers before.

If anyone have a clue to how i can minimize system usage that would be appreciated.

This is coming from a very inexperienced user, but maybe you could minimize your server load by restricting more areas of your website to registered users only. Also, you could look into optimizing your code/images for file size. I'm not really sure if these suggestions will affect the server processor or if they will just decrease your disk space and bandwidth.

In addition, the server processor useage is directly related to the amount of server-side scripts that are called/requested. Therefore, you might look into adding some client-side javascripting. I realize that client-side is very limited, but there are some things which could be converted to client-side, thereby significantly reducing the server processor load, which would then make your hosting company happier and all of the other people that are on your shared server happier.

If you think of hosting as a restaurant, the server processor would be the kitchen, right?

I have realised that the problem lies with Xcgal module, and hence i have disabled anyone from posting pictures to my site ath the moment.
Since then the excessive server usage problem has been solved.
But i know this is just a temporarily problem. i havent' tried the latest xcgal addition that was released a couple of days ago, which might solve my problems.

I don't know how many people who uses xcgal module have had this problem, but i have lot of users who upload quite a lot of pictures every day, and this involves lot of system usage as creation of thumbnaails, intermediate pics,etc may cause server instability.

I use XOOPS 2.06 and no other module is causing any trouble at the moment.

1. Visit the following sites and submit the URL for each module. This will shed some light on the subject.

http://www.websiteoptimization.com/services/analyze/
http://www.sitereportcard.com/index.php

2. Consider experimenting with caching on modules and blocks that don't need real-time updating. If used effectively, this can dramaticaly reduce the amount of server resources required.

3. Try using Gzip compression. This may or may not work, but it couldn't hurt to try.

4. Check for updates on all your modules. Some times new versions are released that address such problems.

5. Update your site to the newest version of Xoops. Beyond stability, there are security fixes as well.

Hope this helps.

I've used XCgal for over a year, except I'm the only one who adds images, so I can understand your position if you are having many people upload images and the like.

I've recently added a new subdomain with just the coppermine module which I intend using for a public gallery. My assumption based on your observations, is that the actual copermine script (which xcgal is based from) will be less of a load on the server because it would be the original developers code and have code tweaks.

I do know that xcgal has been at the 1.1RC status for the entire time I've had it and have not seen any further development in it. Whether that will change remains to be seen.

Maybe one solution you can try in the interim, is change your library settings from IM, to GD 2, or vice-versa. Maybe playing with the settings a bit for the module might stop the heavy server load, such as disabling intermediate pictures, or reducing the thumbnail size. Maybe it could be something as simple as reducing the amount of image are being displayed at once per page. Changing the final output quality might help ,and deleteing the original images might serve some purpose as well, although I can't confirm that, or any of the suggestions I offered for that matter. It's a case of trial and error and communicating with your host(s) to let them know you are working on a solution.

Hopfully with a little bit of tweaking you will be able to reduce the impact on your host server. Once my separate gallery installation goes public for the rest of the family and friends, I'm sure I will hear from the host if there is a problem. Maybe this is something you may need to consider in the end, to integrate a gally with XOOPS, or branch outside the box for that feature. It's never easy to decide.