What OS should I use.
 

I've just finish buying parts for a new computer, it's built around the Intel Core 2 Duo 2.1 ghz processor. I was just going to install in it Windows Xp professional with SP 2 until someonte told me that I should install Windows 64-Bit edition to really use the whole processing power. Is this true? If this is true, should I buy again all my applications (lightwave 3D, Premiere, After Effects) to be compatible with the 64 bits version?

I don't believe 64-bit versions of Adobe software exist.

People who have tried Premiere on a 64-bit OS seem to be disappointed:

http://forums.creativecow.net/cgi-bi...868076&pview=t

Adobe have a FAQ here: http://www.adobe.com/jp/products/pre...emiere_faq.pdf which states:

Q: Does Adobe Premiere Pro 2.0 support 64-bit processors?
A: Yes, Adobe Premiere Pro 2.0 works on 64-bit processors. However, it is not optimized for use on them, so you should not expect to see performance improvements.

So, it seems you will use your existing 32-bit versions of Premiere and After Effects. Therefore, you could create a dual-boot system with 32-bit and 64-bit versions of Windows and compare them.

Also, if those applications are available as 64-bit versions, it seems it would be *very* expensive to switch. You'd probably get more value for your money by upgrading your hardware to a much faster processor.