SSRS Hardware Planning

I've done a fair amount of hardware planning for the SQL Server Database Engine. Now I'm doing so for SSRS which I don't have as much experience with. I haven't been able to find much information, especially around RAM capacity and have a few questions. Any responses or pointers to resources are appreciated.

Scenario: 2 load-balanced SSRS 2005 App servers with an independent back-end SQL DB for the config database. Total userbase is about 2000 (not simultaneous), and I'm still trying to get statistics for per hour requests. May also install multiple SSRS instances on these boxes with one of them in Sharepoint Integrated mode (don't anticipate high volume here). Load-balancing is for both performance and availability goals.

I'm looking at the SSRS App servers only and am analyzing amount of RAM, 32 vs 64 bit, and perhaps CPU core count.

1. Does 32-bit Enterprise SSRS benefit from more than 4 GB on a server, using AWE or other memory extension? Or is anything > 4 GB unused at 32 bit?
2. Are there material benefits to going to 64-bit OS / SSRS and increasing memory above 4 GB? (does IIS handle this?), Perhaps to 8 or 16 GB.
3. The boxes will be 2-way, dual core, with possibility of going to quad core. Is increasing core count a better use of budget than increasing RAM above 4 GB?


I've read the white paper, "Planning for Scalability and Performance with Reporting Services" (http://www.microsoft.com/technet/prodtechnol/sql/2005/pspsqlrs.mspx) which briefly (but incompletely) discusses 32 vs 64 bit, and really doesn't touch on RAM at all.


Thanks for any pointers,

Scott