Caching Blocks with Context Module
How do I get Context to cache blocks?


Anyway a lot of block don't use cache by default. You need to use http://drupal.org/project/blockcache_alter to improve the control of what you want to cache. Sadly block cache alter is not compatible with context but a small glue module make it works :) http://drupal.org/project/context_blockcache_alter . But need a port on D7.

So using block cache alter going to do a real performance boost.

To not use block module the answer from Adam S is correct.