I need the most efficient C# RSS reader possible -

I'm developing an app that will monitor thousands of feeds on the web.

I have a simple RSS reader who will do the trick but I am worried about issues of bandwidth and latency - it should be as fast and efficient as possible.

I want an RSS reader / library that chooses a feed and check if it has been updated without downloading any content (for example, by analyzing date headers in response), and bandwidth To reduce the use of local caching, so that the whole feed never re-downloads.

My important metrics are minimum bandwidth and minimum access latency . I do not care about memory usage, disk space, processing power etc.

Is there a library that does it automatically?