In order for you to take advantage of the 64 bit processor, you are going to need a 64-bit OS and software that will also use all of the 64 bits available.
At least that's the way it works for the Intel Itanium. I am no AMD expert and I don't what kind of smoke they are blowing with the "64" added to their product name.
Just like "3400+", this processor doesn't run at 3.4GHz. So does the "64" actually mean 64-bit processing or that it just "runs as fast" as a 64-bit chip?
I am an Intel and ATI man as well. However, I just brought my wife a new laptop with a AMD-m chip and the nVidia 420 Graphic chip. But that's a laptop and not my gaming system.