Hardware Specs?
 

In the past I was running only some smaller forums with just a few users and most of the time I used Boards like phpBB etc.

I was quite fine with my vServer mit 4GB RAM etc.

But now I am planning a bigger forum in the size of Valves community forum but with less users(something around 5000 is planned for the beginning) but with lots of categories and sub-categories.

What hardware is needed to run this smooth and fast without problems? Will I be fine with another vServer with maybe bigger specs?

Is vBulletin able to support different languages so that every user can switch to his favorite? Are there any addons to include Google Ads or Ads in general without complications?

The Forum is planned to run on VB4 until VB5 is finished, is there anything else I should be aware of when it comes to this size?

I am sure I will have more questions soon.