For a long time, the main reason for moving to 64 bit Revit was that it gave you added flexibility to work on larger projects. If you haven’t heard about the 20x rule for Revit, let me explain.
Revit needs about 20 times the size of your Revit file in RAM in order to be able to expand the file fully in memory. 64 bit operating systems and 64 bit Revit give you additional access to RAM (32 bit OS is limited to 3GB, with the 3GB switch) thus, you can work on larger projects on a 64 bit operating system.
We see another reason to switch to 64 bit, stability.
The Basic Rule of Stability and Memory
In general, 64 bit operating systems running 64 bit Revit are about twice as stable as 32 bit operating systems running 32 bit Revit.
Our Customer Error Reports (CER) and Customer Involvement Program (CIP) help confirm this.
The Reason for 64 bit Stability
Fundamentally the only difference in the software is that 64 bit software, in general (all 64 bit software), allows more access to memory. Based on the data and what we see, this seems to be the underlining cause why 64 bit is more stable. Access to more memory means that your system isn’t as taxed when running Revit and the software isn’t crammed for memory space.
You may ask, “Well, can I just use the 3GB switch to get access more memory on my 32 bit system and it will be more stable?”. It actually turns out that it is possible that the 3GB switch may be contributing to the problem, not helping to solve it. The 3GB switch actually impacts the amount of memory that is available to the operating system, reducing its available memory by one GB (and allowing that memory to be used by the application instead). This in turn can impact other items on the machine, a big one being graphics. Turning on the 3GB switch can impact the graphic cards ability to use the memory that it is normally given by the operating system (that is now given to the application). This can not only cause problems with Revit, but with graphics in general on the system. While turning on the 3GB switch will give Revit access to more memory and allow you to work on larger Revit files, it may impact the stability of Revit itself.
Wrap Up
If you are looking to take full advantage of everything Revit has to offer for Building Information Modeling and you work with large projects, the benefits of 64 bit get more compelling all the time.
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I'd also recommend taking a look at this post: http://www.techspot.com/guides/177-windows-install-32bit-64bit/ It gives some additional information about Windows 7 64 bit that you might find useful.
Posted by: Harlan Brumm | July 21, 2010 at 02:18 PM
Very interesting. I wasn't aware that stability and memory went hand in hand. Is this correct for any system disregarding it's size?
Posted by: software testing training | July 22, 2010 at 05:54 AM
just wanted to know to take full advantage of revit 64bit is there like an option in the settings where we hav to configure on how much ram the software can use? because some 64bit softwares hav that setting and by default are set to either 3gb or 4gb and in some case like my PC has 8gb of ram?
Posted by: Ankit_surti | July 22, 2010 at 07:04 PM
There is not an option in Revit to control the amount of memory it can access. Revit 64 bit will take full advantage of whatever memory you have, no matter how much. For your machine, Revit will use all 8GB, if it needs to.
Posted by: Harlan Brumm | July 23, 2010 at 09:05 AM