Windows 7: Upgrade question regarding wattage

So let's say I have a 450w PSU and want to get something like this:
http://products.amd.com/en-ca/Deskto...il.aspx?id=509

So it says that it's wattage is 125w. So does this mean that the processor requires at a minimum a 125w PSU? If not, how to I calculate what kind sort of wattage I'd need if I wanted to majorly upgrade my PC?

That means that CPU can use up to 125watts. Use this power supply calculator to determine your needs

eXtreme Power Supply Calculator

That's nifty! But is there a method I can use on my own to determine the wattage I'd need?

Not really, unless you know the exact power draw of all of your components. I've been doing computers for years and I always use these web sites with power supply calculators to estimate my needs. You would have to know hundreds of video cards and such off the top of your head, as well as hundreds of CPU's to make the estimate.

Alright. Thanks. That's very helpful.