Correctly configure opcode and change MYSQL settings according to specs from Prestashop's web page

Our hosting provider has provided mixed explanations for running opcode caches. Originally we were told changing to a DSO handler would be the correct format for running opcode caches such as APC and eAccellerator. Provider now: "We would be happy to assist you with this question, and there should not be any effect to the modules that you currently have installed. However, as you are currently using the DSO Apache handler for PHP there are known performance issues with this PHP handler and this could be the cause of some of the issues that you have been experiencing. Please also keep in mind that to use eAccellerator, Memcached or most of the PHP caching features you will need to switch to using FCGI for the PHP handler for Apache. " According to [login to view URL] 9. Install a OP-Code caching tool like eAccelerator or APC "eAccelerator is a free PHP code accelerator & optimizer. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution. eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 times." Since the first time eAccelerator was installed (DSO style) I haven't seen *any* increase in "the speed of your PHP code by 1-10 times." Same applies to Memcached. If there is a difference, it is so negligible, it's not even worth it to be running. Simply put: The final idea is to get a *correctly* working opcode cache installed *and* working. Finally to complete the project simply setup step 10 according to Prestashop's blog: [login to view URL] 10. Tune your MySQL configuration, and check your SQL query cache value Ask your hosting provider to dig into the MySQL configuration and to check the query_cache value. This value should be at the very least “512M” (512 Mega-bytes)." Step 9. from this article: [login to view URL] 9. Use Memcached min 512m