"It was the best of times, it was the worst of times..."
Recently I came across two database servers, one with fast execution times, the other with slow execution times. Both machines were running windows server 2003, both had similar hardware, both had similar disk access speeds, yet one was over three times as fast as the other.
We puzzled over what could be the cause of the difference.
Can you take a guess?
Turns out the fast machine was running the 64-bit version of Windows 2003 and the slow one was running the 32-bit version. The fast 64-bit machine could load entire tables directly into its 8 Gig memory making it much faster. The other machine, when it wasn't hammered by disk thrashing, was probably wondering what it was doing with all that extra memory it couldn't access.