Hmm, been using it since I found it in late .18 early .19, sometime around then. Aside from that, lower your graphical framerate a bit (how fast the images refresh), and there's some sort of g-input thing or something, that checks for commands. If it's set high, it checks fast and never misses a button. If it's slow, it might miss it if you press a button, but usually the "low range" is very fast and catches all commands. Both of these can help FPS greatly and are often overlooked in favor of kitten slaughters.
Try making the corner wall tiles slanted, this should make diagonal walls easy and (with the default tileset) should be very easy to change using MSPaint or such. Instead of building a circle and having it look like "stairs", it looks like "smooth ramps". I downgraded my Phoebus tileset so I could get my diagonal walls. So much better!
Poking the init, you can change the priority higher so that DF requests more CPU power, can push up your FPS while leaving non-essential background things like chat programs and music players to make due with less. I also changed my announcements to pause and recenter every time a dwarf dies, so that I don't miss any important deaths, and changed the init.txt option to give a half-second break after the game pauses. This way, when someone dies, I don't accidentally hit some key and unpause/mess up what I was doing.
There's a lot of little tweaks you can make to enjoy the interface more. I turned off the FPS gauge at the top, it stressed me out too much to watch it slowly fall