This article is still under construction........

 Let's have a look at different points:

• Apache with PHP module consumes a lot of memory because each request is handled by one process.
• The worker MPM uses a thread based architecture as opposed to the pre-fork MPM which uses a process based architecture; the architectural differences between the two Multi-Processing Modules means that the worker MPM has a lower memory footprint.
• The pool of fcgid-invoked programs is shared between all httpd workers.
•  

 Related links.

One of the best feature of Drupal is the image api; that will help you a lot in managing all of your images to make with the help of the module imagecache all kind of modifications, like resize, crop etc..

In PHP you need the GD Graphics Library for dynamically manipulating images. You need to recompile PHP with the GD library of image functions; fortunately apt-get will help us for this to work.

The package is called php5-gd

This is the first step to boost your drupal site (or any other aplications using PHP). More ways to improve your site are to come.

APC (Alternative PHP Cache) is a PHP extension that will boost up your php scripts. It is part of PECL (a repository for PHP Extensions)

1. In my ubuntu server "make" was not installed and you will need it to compile the code of the uploadprogress pecl extension. apt-get install make
2. Next we need "phpize" which will compile the code to make it part of the php library. apt-get install php5-dev
3. The next line will download and compile the pecl extension.