ram and processor of access point

I am talking about access points.All companies write the specification/detail of access point. From its detail how we can identify/find-out that how my clients(INTERNET users) handle by AP simultaneously.My Friend suggest me that the processor and ram gives us guess means from ram and processor we can identify that how many user the access point can handle(give 100% perfect INTERNET)
Whats your view???

Wireless is more of the limitation than the routerboard itself. I would say 30 to 40 max users per wireless card. CPU becomes important when the router has to process a lot of packets.