Revit Architecture Whitepapers
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=8480751

Autodesk FBX-Based Revit Architecture 2009 to Autodesk 3ds Max Design 2009 Workflow
http://images.autodesk.com/adsk/files/revit_to_max_whitepaper__2sept2008.pdf

Revit Platform 2009 Model Performance Technical Note
http://images.autodesk.com/adsk/files/revit_platform_2009_model_performance_technical_note.pdf

Multiple-Core / Multiple Processors

• Although the Revit platform is generally not optimized for multi-threading, multiple-core processors reduce cycle use by other applications running concurrently. Some reports show as much as a 20% increase in Revit platform performance in a multi-core or multiple processor environment.
• The Revit platform’s rendering function is optimized to use up to four processors. The Revit platform will share processing time with one of these four rendering processors, so there is no exclusive gain for the Revit platform in making available more than four processors. Additional processors may be desired if other computationally-intensive applications need to run while the Revit platform is rendering.

64-Bit Windows Operating Systems

• 64-bit operating systems place no practical limit to the quantity of memory available to applications. 32-bit Revit-based applications will access between 3 and 4GB of RAM in a 64-Bit OS environment if at least 5GB of total memory is available. The Windows OS will always reserve at least 1GB of memory for OS services and hardware management. A total of 8GB of memory is recommended for such systems to make available 4GB of memory to the Revit platform, at least 1GB for the OS, and additional memory for other commonly used applications to run comfortably alongside the Revit-based applications.
• A 64-bit OS will provide similar performance to a 32-bit OS. However, due to the capability of the Revit platform to access additional memory, Revit may exhibit increased stability and performance when editing larger models.