Greetings,
I am planning to build a site with over 5000 'Pages'. There will also be 'posts' to supplement the main content in the 'Pages'. Can I build such a site with Atahualpa without compromising the loading time of my site? Please give me necessary directions on this point.

This has more to do with WordPress and your host than the theme. I would check on the WordPress forums and check with your host on handling the bandwidth/data.

Greetings, and thank you for the quick reply. I have checked the Wordpress forum and have not found any clear cut answer for my question. Can you please help me ? My webhost is Hostmonster.com.

If you couldn't find an answer at wordpress why would you thing this forum could help you?

I don't think you will find an answer, there are two many variables

You are going to have to do some testing and come to a conclusion yourself.

Please let us know your results.

Because this forum has great gurus like Juggledad and lmilesw.
lmilesw ... can you help me?

And you probably won't find a clear cut answer as there are many variables as JD mentioned such as what is on the 5000 pages, how many visitors per day will there be, etc, etc. This is certainly not a theme related issue. I would check with your host.