what is the easiest way for opcode caching with PHP/Apache?

Question

I was thinking to use opcode caching for performance profit

what is the easiest way for opcode caching with PHP/Apache ? and what are the performance improvements ?<

Answer 1

Other popular options are eAccelerator and APC.

Performance improvements will depend on the web app you're caching. Here are some benchmarks for the Drupal CMS using APC and eAccelerator, and here's the same site's tutorial on installing APC (nice and easy).