Installing and upgrading help

I first installed a v1.9 on a 1 or 1.2ghz cpu (from memory, I don't think it was any earlier than that as the previous machine I was using was very low) and it ran alright... but.. there is always a but... it had a memory issue and that was only a small peer to peer, using Xampp, never did that again. The more RAM you can give it the better. On any server, it is always best to have as much RAM as you can get anyway. I don't know about what sort of performance someone like Open University has with their 35,000 plus Moodle users (so I understand), but in that circumstance a server farm possibly segmented for each discipline or faculty would be most advisable. I reckon that is how I would set it up anyway... lots of servers, sure, and each faculty with their own Moodle, be something of a pain to administer, but with that many users it would be affordable to have more than just one network administrator..

> What is cpu requirement?

http://docs.moodle.org/en/Installing_Moodle#Software describes the software requirements. Any hardware capable of running these are suitable.

> How does cpu reuirement change with user count?

http://docs.moodle.org/en/Installing_Moodle#Hardware says, "The general rule of thumb is that Moodle can support 50 concurrent users for every 1GB of RAM, .." Except for that there are no simple for user count vs. CPU. You will find longer answers in
- http://docs.moodle.org/en/Performance and
- http://docs.moodle.org/en/Performance_FAQ