Yes, that is an impressive piece of hardware. Well, as long as you can call a daughtercard hard, and this toothless chassis bites.
The software is a different story. I hope that you are not going to load all that bloat into your machine, that'll sink a freighter.
What was the question, whether these are enough for 3000 users? How greedy are they? If you've checked the initial pointers to this forum, you know that this group tries to "standardize" the user: http://docs.moodle.org/22/en/Performance_FAQ#How_do_you_define_.22concurrent_users.22.3F.
I know, it's all jargon. May be you can describe how this machine will be utilized, from the users' point of view.