A client is dependent on the History | Items function to look up sales info about customers and items.

Yesterday, it took about 10 seconds after clicking Load to generate the transactions (they have a ton of history). Today, using the same selection criteria, it took a couple of minutes. This happened on multiple machines (we tried three), using a variety of XP and Win7 systems.

I'm not sure where to start troubleshooting this. What matters most to the Load speed? What could have changed overnight?

Thanks

Steve