Re: msyql 5.0.22 and multi-core server support

[Rick James]

All versions of MySQL use multiple cores -- but only one core per connection. Not even PARTITIONing uses multiple cores within a single connection.

Each of 5.5, Percona, 5.6, and 5.7 is to be more efficient than its predecessor in allowing more connections to run concurrently without stumbling over each other.

5.0 could handle about 4 connections _actively_ doing things at the _same_ time. (Any number of connections can be sitting idle without impact.)
The latest 5.7 raises that to more like 64.

Do not bother upgrading the server, at least not for CPU power. You have essentially the maximum you can use with 5.0.

But...
I have addressed literally thousands of performance issues. Almost _never_ is the solution to get more or faster CPUs. Usually the issue is solvable via schema and/or query changes. To assist in analyzing slow SELECTs, please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
* SHOW VARIABLES LIKE '%buffer%'; -- cache size
and surround them with [ code ] and [ / code ]
How much RAM do you have?