website performance benchmarking

So my company has just revamped a large commercial site that receives 100k+ page hits a day and some people are seeing performance issues compared to the old site.

Does anyone know of any performance benchmarking tools to show site performance as a whole especially related to other sites we might specify?

The site is a compiled .Net site and we're looking for an understanding of performance compiled vs uncompiled, page render time, database performance, under heavy load, etc. We can use Yslow for most of those answers but its really time consuming to go page by page in a huge site and pretty hard to track.