PS2 is a terribly coded game, as is Arma 2, Skyrim, SC2, etc. All of these games are single threaded, some are touted as multi threaded, but the coding is a joke to the point that any CPU will have a hard time with it. But, it depends on the game, if the CPU scales well, or gets slammed, or runs a game like a webpage. If you are worried about your temp variance, don't be. The socket temp and core temp are two different beasts. I have had CPU's shut down when the socket temp was still under the max safe temp, because 1 core was running hotter than the others, gimping the system and causing shut downs. It is unfortunate that we don't yet have a great temp reading software at the core level, but it is what it is. Also, you can't say that a socket temp will always be higher than a core temp. I have had and seen CPU's do quite the opposite..
If life was easy, we wouldn't have lemonade! I love lemonade!