A friend just passed me this whitepaperthat shows a 75.9% increase in database performance by just buying a little higher priced processor.
The test was done by Principled Technologies on a new Dell PowerEdge R710 server and compares 2x Xeon E5520 (Nehalem) vs the same R710 server with 2x Xeon E5506 (Nehalem) running Microsoft SQL Server 2008.
I did a quick price check on dell system on-line configuration tool today and the price difference was only $300 ($150 per processor) in the standard R710 configuration. With a base server price of $5,345, the price delta is a little more than 5% in price for a 75% increase in performance.
Wow! … a 75% gain in database performance for just $300
Of course, you'll need a Nehalem based server first - which can pay for itself in an estimated 8 months.