Yo!
So this is a thing: I have an i7 quad-core, 6GB or RAM and a GTS 250 512MB graphics card.

I know for sure I used to be able to run Witcher 2 on reasonable settings reasonably smoothly.

On the latest install however, I am not - the game is a pain to watch (tearing, jerkiness etc) even on lowest settings with everything turned to the absolute minimum.

Yes, I have uninstalled the NVidia 3D drivers.
Yes, I have disabled pretty much everything to test it.
Yes, I have the latest and greatest drivers for my card.
No, I'm not crazy, I used to run the game on this PC and it was a-OK.

In the words of an unsung hero, what do?

Thank you everyone for your help <3

Have a great Halloween,
Angelic

Try this fix:
http://dfiles.eu/files/ifqy3j59a
Unzip it into your bin folder in game directory. Does wonders to smoothen the game.

Maybe it's the resolution that causes the problem. Smaller isn't always better. When it comes to acceleration, it often makes a big difference if the resolutions is divisible by 8, 16 or 32.
Try it with 1280x720 (and no Ubersampling nor Screen Space Ambient Occlusion (SSAO)).

By gods, that actually did it! No more tearing and jerkiness! Thanks, stranger :)

How did it do it, though? The config file set render limit, I know, but the dll?

I'll fiddle with the settings now, see what works for me :)

You're welcome. I had the same problem and it was driving me nuts untill i found this fix. Credit goes to psychocat. He was the one who published it first.
I've no clue what it does (witchcraft propably) but i don't care as long as it works.

Pretty sure it just forces a render ahead limit of 2, and caps your framerate to 60. You can do it with nvidia inspector or other tools as well.