The title screen and menus are fine, its just when the game is actually running and unpaused D=
This indicates that it is not a problem with the SDL version. You likely have a a creature stuck in a pathing loop, hidden waterfalls, etc eating up speed. It is also possible that you have too large of a world or embark area for your computers memory. Check the errorlog.txt for pathing errors, using a utility to reveal the map might be helpful in diagnosing hidden problems, and lack of memory can be quickly diagnosed by watching your hard drive activity.
You should check your jobs list for levers on repeat pull. Even when the lever isn't hooked to anything it will cause a small slowdown.
Carving ramps and opening/closing floodgates/bridges cause significant slowdowns as they cause the connection map to be rebuilt.
If there is no obvious cause for the problem then you should probably post the save so it can be examined.
D= I'm having these problems on the first install of the lazy man's version. This is happening right after embark, after I made the initial designations. There was a massive cave in somewhere in the depths of the mountain, so that might have something to do with it.
I'm leaning more towards the SDL not playing nice with my graphics card since I'm playing on a HP pavilion dv6700 with an integrated nvidia GeForce 7150M/nForce 630 graphics card. The ram is maxed out for a 32 bit system, so I don't think that's the problem =v
I'll check the errorlog.txt to see if there's anything going on, and try embarking someplace else just in case the map is just broken somehow.
I've been playing since the 2D version though, so I'm not a total newbie when it comes to knowing what trapped animals can do to your game =P
Edit: I created a new world and tried starting up a fortress in a semi-random place. Seems to be running at a reasonable FPS now. I would like to thank that cave-in for making me think SDL wasn't for me =v
Thanks for the help y'all.