Multicore processor IIS 8

Hi,

I'm working with win 2012 Srv and SQL 2012, on muticore processor Server (2 CPU, 16 fisical core, 32 virtual cores, 48GB RAM).

Now I'm lookin that web applications (classic ASP) working fine, but they don't use more than 3% of cpu, So I would like to know how I could use more Cores for IIS and improve System web performances.

Thank you.