What Does 64-Bit Vista Get Me?
More bits gets you access to more memory. The processor inside your PC communicates with your system memory (RAM) with numeric addressing. Thus the maximum amount of memory a 32-bit processor can address is 232 bytes, or 4 gigabytes. Newer 64-bit processors—not to mention the 64-bit operating systems that run on them—can address 264 bytes of memory, or 17,179,869,184 gigabytes (16 exabytes) of RAM. (17 million gigabytes may sound like a lot of space now, but it won’t be long before you’ll be taking baby pictures with an 8-gigapixel digital camera.)