CPU and load usage

I am planning to run Asterisk in a Pentium 4 2Ghz CPU with 1 GB RAM. I read the white paper and mentioned that asterisk requires quite a lot of resource when processing simultaneous calls. If we use it to support 8 concurrent IVR calls, how much resource will it take? Is my current server specs sufficient? Anyone can share on planning the hardware requirements for Asterisk? We are planning to use Dialogic card.


We use a box with the same specs and a t100p to run an office with about 20 users. The memory usage usually hovers around 400Mb and the CPU load usually never goes beyond 10%.