Hello, I tell you, what is my scenary., I have a vmware virtual machine install in ssd disk. The installation is clean because I installed yesterday. First I installed mysql server 5.5 via apt-get. I restore my db and I made firsts test. the first query return 2,8 seconds for one total 3500000 of register of table, with 3 fields in mysql. In other vm with same features , I install Percona server. The same query, returns 6,47 seconds with percona server. In both case there weren’t any optimizacion. Why mysql 5.5 return better result that percona?