64 bit M$ operating systems

Source
Benefits

• The additional computing power,
• the additional security and
• obviously the benefits of breaking the 4Gb memory barrier

So what could still stop you from going 64 bit?
There’s no doubt that 64 bit is better but the problems standing against people who want to upgrade include…

• Driver support – Less of an issue for newer hardware, but some hardware vendors still don’t have 64-bit driver support for their products and, sadly, many people only find this out after they’ve installed a 64-bit OS.
• Firewall support – There is still no free stand-alone firewall that runs on a 64-bit version of Windows. Why? Currently if you want anything other than the standard Windows firewall these companies will force you to buy their not-really-worth-the-money security suites.
• Software support – Apple were late to come to market with a 64-bit version of iTunes and they’re not alone. There’s still a lot of software that won’t run on a 64-bit OS.
• Run the 64-bit version of Internet Explorer (for better stability and security) and visit YouTube, or any other website running on Adobe Flash. You’ll receive a message saying that there’s STILL no 64-bit version of the Flash player.

Drivers support, software use more than 4GB of memory and multiple core CPU’s are key to 64 bit OSes (of Micro$oft) going mainstream.