Below is a somewhat fictional somewhat realistic view of upgrades.
"I think the database is broken" was my first call this morning.
"OK, what error message are you getting?" was my reply. Since I knew we changed some things over the weekend, I figured something got left out and needed fixing.
"My process that normally takes 38 minutes is done in 3."
"OK, does it error out?"
"Do the results look right?"
"So why do you think it's broken?"
"Because it finished in 3 minutes."
"Well, we upgraded the database version this past weekend and put the database on a faster host, so that's probably the difference."
"But it used to take 38 minutes."
...long pause on the phone by me, expecting something else...
"I can slow it back down if that's what you want...."
On the flip side, I go to my developers to see how things are going and they report increases anywhere from 4-10 times faster depending on how much the db is being used. One savvy developer corners me and says something along the lines of "Can't we move this db to a faster host?"
"Huh? This is the almost latest, greatest, fastest host there is. You've got 3.0Ghz of Dual Core processing power underneath your db where before you had some clunky Sparc processors."
"You know there's 3.2Ghz processors out, right?"
"So, let me get this straight. You're 10 times faster than Friday, and you want to be 10.1 times faster?"
"Yup, that extra speed will really help."
"I need to get back to my office, call me if you have any problems."