This article http://www.animotion.nl/en/blog/cs5-should-you-upgrade/ mentions the following
64bit: In a 32bit program, the maximum memory (RAM) that can be used is 3 GB. Photoshop, Premiere Pro and After Effects CS5 are 64bit programs and can use all of the memory in your computer. This makes the program more stable and faster, especially with complex projects.
Can anyone confirm this? I'm on the fence about upgrading because I only have a quadcore 2.33 with 4gb of ram.
afaik CS5 works faster on any 64bit system. i have dualcore, 2Gb RAM, no mercury playback and Pr works a bit faster.
if u'll just upgrade your videocard to some cuda, u'll get much more space for real-time preview and up to 10 times faster playback.