PC running in the 95-99% range when broadcasting

Hello,

I have a 2 BMD Intensity setup running off my HP Pavilion P6520F Desktop PC Athlon II X4 635(2.9GHz) 6GB DDR3 1TB HDD Capacity ATI Radeon HD 4200. When I'm broadcasting in h.264 720p the CPU is really working overtime. I'm worried that one day it will just crash on me.

I guess my question is 2 fold. How can I lower my CPU without sacrificing the quality (not to mention that I want to add on a record to disk that I haven't even attempted yet)

And secondly, if I were to start from scratch on a new machine what would one recommend for solid/reliable performance?

Many thanks!

Randy