|"without opening the cpu"|
You can't open a CPU, it's a chip cut from a silicon wafer: How to Create a CPU
I think you mean you don't want to open the computer case/tower? If you would have posted the make/model of your computer, one of us could have told you what you have. Or you could have looked it up yourself by going to the manufacturer's website.
Try using this: CPU-Z 1.62