I know tons of people at small businesses who work with or on machines that are considered "new". But these new computers are as cheap as possible. $250 for a computer is amazing. Disk space is the greatest (maybe 500GB, but it's a spindle disk). RAM is starved (lucky if there's 4GB). CPU is typically, at best, a Core i3, and probably more like a Celeron, Pentium, or often AMD.
The real irony? Despite having a poor-man's CPU, its utilization is usually really low because of the amount of swapping that occurs to a spindle disk. Having superlarge pretty fancy apps (that, honestly, business users don't care about for productivity) really kills the user experience. That's, of course, assuming that the app doesn't have other shortcomings. Bugs and counter-intuitiveness really hinders things too, particularly when certain problems only show up when things run slow.
First thing I recommend to them is to invest in an SSD and some more RAM. But the $100 for that is often out of the reach of these people.
So, to reiterate: cheap resources to you doesn't mean your desired audience also considers these to cheap too.
Even if you would like to spend that time trying to optimize your application, my experience is that it's very difficult to get the mandate to do anything beyond spending a few hours on it when you could be spending that time making some new sellable feature.