There is a utility you can download that will tell you. It will also tell you the make of everything in you machine, without having to open the case. (for instance your MB)

<a href="http://download.cnet.com/downloads/0-10102-100-8596466.html?tag=st.dl.10001-103-1.lst-7-1.8596466" target="_blank">http://download.cnet.com/downloads/0-10102-100-8596466.html?tag=st.dl.10001-103-1.lst-7-1.8596466</a>