I had same troubles time ago, but then I changed this settings, and now is little bit better than before, so maybe help you too:
before: VSync disabled (options in first window of game)
now: VSync enabled
before: Triple buffering disabled (in graphics settings - for your hardware, mine is Catalist Control Center for AMD)
now: Triple buffering enabled
before: max fps +200 (options in first window of game)
now: 70 / 100
...also, almost all options are near lowest parameters, but now is ok with DX9 (with Windows 8.1, but before only could play with DX7 at windowsXP SP3)
all my hardware is same than before, but now I feel game little bit better (ofc you won't have best graphics ingame, but at least playgame feeling is near to ok)
I'm not saying that will work in your PC, but maybe... btw, try different graphic options until see if troubles dissapear or improve.
good luck!
vertical synchronization is supposed to drop your fps down if it's higher than refresh rate of your monitor in case to save gpu power and energy. 60 hz refresh rate = 60 fps with vertical sync. if your gpu has enough power to render more. with vsync disabled your framerate is higher than refresh rate of your monitor which leads to the effect when there are lines on your monitor and above the line is different frame than under it. on the other hand it reduces input lag of mouse and increase the game speed
tripple buffering is supposed to raise your fps if it's lower than refresh rate of your monitor. so again 60 hz monitor = 60 fps. but every maybe 6th or 7th frame is the same like frame or two before it. so - if enabled, you have constant fps and smooth video without tearing, but the gameplay aint smooth, with 40 fps before you have 60 now, but 20 frames are mostly duplicates so the game feels slower
fps limit has no sence if you are using one of these tools
as we are talking about low fps, vsync and lower fps limit have no effect. trilinear buffering may help in the way that your video is not tearing, but the game feels slower, it may feel like you have double or triple ping