Hi Using Maya 8.5 on Precision 690, OS XP Pro x64, 8 gig RAM

I have just switched from XP x32 to XP x64 and added more RAM to my PC but don't think Maya is accessing it for rendering.

I know there is somewhere you can see how much RAM Maya's Mental ray render uses and also you can customize this but I don't know how to locate it.

Anyone?

Thanks, T