Game Accelerator has updated with optimization settings for Second Life and other games. It does help with memory leak in that it clears your memory without slowing your system down. (Have to select "Enabe Intelligent Memory Optimization" upon startup.) But this definitely works! It is shareware though.
What's new in v6.0:
* Added special game optimizations for: Madden NFL 07, Dungeon Siege 2: Broken World, Civilization IV: Warlords, Bad Day LA, CivCity Rome, Reservoir Dogs, Beyond Divinity, X3: Reunion, TOCA Race Driver 3, Second Life, The Ant Bully
* Improved special game optimizations for: World of Warcraft, Guild Wars
* Improved support for latest Intel and AMD CPUs
* Improved support for the latest Nvidia and ATI video cards