I am one of those people who really tried to save up on memory while using 3ds max by constantly checking up on the polygon count and then checking on my rendering settings, which was set to the V-Ray rendering system. I also look at 3ds max's memory usage on the status window while it renders the scene.
What I first noticed while I was rendering an image on my girlfriend's laptop was that it was already using up almost 2GB of memory and still 3ds Max is running without any trouble. What is exactly amazing about that you might ask? Well, I had problems rendering a scene with the 32 bits 3ds Max crashing up on me every time it goes beyond the 1.5GB memory usage on my old 32 bit windows system. This computer I was using at that moment was able to handle the memory usage really well and went over the memory limit that I once thought would crash 3ds max. I suddenly then had this memory of a friend of mine once telling me the difference between a 32 bit computer and a 64 bit and how a 64 bit system is much better than the 32 bits. That time I was not able to understand what he was talking about and was really hesitant on converting to a 64 bits computer system. But now, I understand and believe him clearly that a 64 bit system is a better and much powerful system to work on.
Researching on the net, I found out that a 64 bit system can handle as much as 128+ GB of RAM or memory and if your software is programmed to run on a 64 bit system, it may be able to maximize that much amount of memory. This compared to running on a 32 bit system which can only handle up to 4GB of RAM and the 3d bit 3ds Max which can only handle up to 2GB of RAM, I'd say that there's no competition and that 64 bit would win every time.
On the speed factor, especially on the speed of the rendering, a 64 bits 3ds max has no apparent difference with the 32 bits 3ds max and they seem to render out exactly at the same time. The only benefit, and is one of the important factors, that I think why one should convert to 3ds max 64 bits is its memory usage. 3ds Max 64 bits is only limited to how much memory or RAM is installed in your computer. And, I guess, that if you have around 128+ GB, which is already considered to be an unlimited resource to today's standards, 3ds Max 64 bits may be able to maximize the use of this amount of RAM.
So, knowing all these information, I had my computer formatted and installed with a Windows 7 64 bits version and then installed the 3ds Max 2010 64 bits version and I had much more fun rendering there after.
The jump to Windows 7 from Windows XP was also no regrets for me as I think Microsoft has done a wonderful job with the operability and usage of Windows 7.