how do I set the environment variable for the parfor temp directory

I have one of those really fast pci ssd's and I wanted matlab to use it for temporary files. In particular, this mattered for parfor worker variables. Changing it did cause some anonomolous behavior in editor (sometimes on an error it opened the temp file, not the actual file in my work directory. Anyhow, someone gave me a path variable to set (it happened in adding a something to some environment variable like temp -- I think it was a windows variable.) It was something like (path?)=%path%g:\matlabtemp;

Does anyone know where matlab throws the files to be used by parfor workers and how to redirect that to a particular directory (on a particular drive?)