I'm looking for WP cache plugin which is able to handle large number of pages. approx. 1 mil. I'm considering W3 total cache , WP super cache and few more , unfortunately I don't know which one is the best for large site. Can you suggest one ?
they ran some Benchmarking for the top WordPress cache plugins and also of combination of different DB and widget cache plugins.
I wrote a pretty extensive article about WP Super Cache, Autoptimizer, and using a CDN network called WPCDN (only $6/month!) here.
I personally like WP Super Cache over W3 Total Cache because it's a lot easier to use.
I've been happy with Quick Cache - straightforward to use, works on multisite and a bit lighter but not as configurable as W3 Total Cache.
W3 Total Cache's killer feature is being able to offload onto a CDN which is why sites like mashable.com and smashingmagazine.com etc use it.