Hoard to replace malloc

http://www.hoard.org/

Comparison

http://developers.sun.com/solaris/articles/multiproc/multiproc.html

Others:

Google's tcmalloc

http://goog-perftools.sourceforge.net/doc/tcmalloc.html

PushLock in Windows kernel

http://blogs.msdn.com/ntdebugging/archive/2009/09/02/push-locks-what-are-they.aspx

Garbage Collection for C++

http://hnxgc.harnixworld.com/

http://hnxgc.harnixworld.com/benchmarks/MicroBench/