Are these specs decent for 8 lines and 15 extensions?

For a small business. They already have a router and about 15 workstations and a server. Just a normal business not heavy volume in either telephony nr database work.

Intel® Celeron® D Processor 325 (2.53 GHz, 533 FSB)
512MB RAM
40GB HD

I will be using the digium cards. Will asterisk run well?

Are there any specs anywhere to help estimate hardware requirements?

Thanks

Maybe this will help

voip-info.org/wiki/view/Aste … mensioning