I will have to create a multi-threading project soon I have seen experiments ( delphitools.info/2011/10/13/memory-manager-investigations ) showing that the default Delphi me
You could use TopMM:
http://www.topsoftwaresite.nl/
You could also try ScaleMM2 (SynScaleMM is based on ScaleMM1) but I have to fix a bug regarding to interthread memory, so not production ready yet :-(
http://code.google.com/p/scalemm/