I have a similar machine except with 4G of ram; however, it runs the database and webserver for Moodle. We have 1000 students, 100 teachers. Performance in a WIMP environment was rather poor. I would say that from what I have read on the forums, the things I would try in the following order would be:

1) Install some type of PHP Accelerator (eaccelerator, apc, etc.). I do not recall what is available for Windows since I ended up upgrading to Linux.

2) If the accelerator does not give you the performance boost you need, try using Apache instead of IIS. I have heard that performance is better with Apache than IIS in a Windows environment.

3) If that still does not give you the performance you are hoping for then I would consider changing the OS. As I said, I eventually upgraded our server to Linux (I used Ubuntu because there were easy to follow step-by-step instructions on HowToForge.com and because it allowed for a nice GUI, windows like interface).

I am running our server as a LAMP server with apc for php acceleration and have been very happy with the performance. Happy Moodling!

> 1. My servers hardware spec enough to support 600 users. What if the users become 6000 next year?

They will have a problem then!

Seriously, for the powerful hardware you have, the performance is very poor. You will notice, that lot of people in this forum can help you, if you are using some sort of Unix. Many of us, at least myself, are clueless in the "closed" Windows environment. You might have a better chance in the Windows-Forum http://moodle.org/mod/forum/view.php?id=6799

> 2. Will Windows Network Load Balance help on this issue?

Load balencing is the classical approach to high performance webservers. See for example http://moodle.org/mod/forum/discuss.php?d=62896

Since your car seems to a have pulled hand-brake, how much a turbo-charger will accellarte it, is a difficult question.

> 3. Many users in the forum suggest that the Moodle is performance much better on Linux based platform, I plan to try out on RHEL4.2., any comments

No operating system is "faster" per se. It depends on how much you understand and able to tune it. The difference between "closed" systems like Microsoft Windows and "open" systems like Linux ist that, the open system is open! You can look in to it, put your hands on it, start tweaking! And the whole fun is free!

Since you suggest RHEL, I guess you have the know-how. In that case, for web-servers at least, Unix is definitely the way to go. For people who want to start from scratch but want to systematically build an understanding of Linux, I've just started a small project. http://moodle.org/mod/forum/discuss.php?d=64984

You, or anybody else who is interested, can write to me personally. Please note that any follow-up discussion on that topic belongs to the thread mentioned above.