Yeah, putting a bit of thought into your coding can make a lot of difference. I rarely make very efficient code from the start though (he said as if he'd done a load of games in assembler) - early on I focus on getting the framework right and things on the screen, and then later when I can move things around and see them working I start optimising.
On this project I'm drawing on a backbuffer and moving that to the screen area, and that is pretty slow the way it is right now - which is slowing things down, but I'm expecting to get a 100% speed increase on that routine once I put my mind to it.
...the little mind I have.
Yeah, well, so...a bit of 'fiddling' can make a bit difference.