How to save my server RAM/Memory?

Follow the steps give below:
1.  GZIP Compress your website contents, by doing it you can save your server resources and increase the speed of website. For more information check this link : http://betterexplained.com/articles/how-to-optimize-your-site-with-gzip-compression/ 

2. Make sure to use FCGI rather than PHP5 as php execution server so that you will save server RAM memory as well as CPU%. To convert PHP5 to FCGI, refer this post: http://www.timesmangalore.com/webguru/?p=523

3.  Re-size Images: Please upload exact size of image related to embed size. Eg: If you are embedding an image with an article with 500X500 pixel size, then you must upload same size of image to the server, uploading higher size of images cause website slowness.

4. Remove un-wanted plugins, modules if you are using phpBB, WordPress, Joomla! etc. There is a chance that the plugin file is served with your website even if it is de-activated. So, make sure to remove them when you are not using it.

5.  Always use CSS instead Tables. And Do NOT have many @import css files. Reduce the number of duplicate Image/js/css codes ad files.

6. Do NOT list more than 8 to 10 posts per page, the customer/visitors stay on your website depending on your page load speed.

7. If you have business, E-commerce website, try avoiding Flash related stuffs.

8. Once in a while, optimize your database.

9. Keep monitoring  script logs and error logs, make sure to see which database table is getting max queries. Block un-wanted traffic IPs etc.

Let me know if you need any help. I would be so happy to help you.