These are my links for 26 set 2012 from 17:24 to 17:48:

• Optimizing Magento Performance – Tutorials – Magebase – Performance optimization is a good way out in such situation. Optimizing a website, you should consider providing two factors:

  acceptable pages loading speed;
  acceptable pages loading speed when N people use the same application simultaneously.

• Magento and Nginx Performance Tuning Services – Magento and Nginx Performance Tuning Services
• Optimize MySQL settings for Magento database – The Tuning Primer is a shell script that allows you to review the MySQL settings and make adjustments to increase Magento database performance and stability. The script will analyze MySQL statistics and provide you with recommendations on how to fine-tune your MySQL server.

  The uptime of your MySQL should be more than 48 hours for correct script work. Only in this case there will be enough information for analysis. Tuning Primer script is compatible with all versions of MySQL starting from 3.23.