G729 on Celeron D


Right now I have purchased 1 g729 license, I would like to purchase more. Is there anyway that I can find out how many concurrent g729 calls can a “Intel Celeron D Processor 325 (2.53 GHz, 533 FSB)” handle with good quality?
I’m looking for something around 8 to 10 calls, would it be able to handle that much?

Thank You