Wolf Rider is correct, EVGA precision tool has a built in fps limiter. Free download from EVGA, works with all Nvidia based cards. For all those that haven't tried precision tool you don't know what you're missing.

I believe you can use MSI Afterburner with ATI cards as well, I haven' t tried frame rate limiting with it yet, but I will.

+1.
I have been using Precision by EVGA for quite some time, some features I really like:
1: Custom fan curves - I use a custom fan curve to control the fan speed on my card, keeps it cooler than the default and relatively quiet,
2: The monitoring - I have the added benefit of having a Logitech G19 keyboard with LCD display, so I can monitor what I want and have it displayed in the lcd display on my keyboard - what I usually monitor is temp, fan speed, vram usage, and framerates. You can also choose to monitor it on screen.
3: The aforementioned frame rate limiter, it works very well. They refer to it as "frame rate target", but it really is a limiter, the target you set is the limit of the fps.

Reading this post I tried Nvidea's 'Adaptive Half Frame Rate' Vsync option (Driver 301.24 - Vsync disabled in CloD) and was very impressed with the results, especially in MP. Locked at 30fps and didn't budge - very smooth!

Good thread..........thanks guys.

+1
I also tried this, and it locked it in at 30 fps and there was no pausing or jumping except with effects like smoke and fire with I think are still not optimized correctly.

sorry guys, but I am no expert and I don't understand what's the advantage of an FPS limiter.

No need to FPS limiter anymore. The stutters now aren't so related with graphics. With particles system problems solved, the sim will run great!

The theory is that if you lessen the range that your FPS can jump you will have smoother game play, example I can range from 0 to 120 FPS at times in game, now if I limit to 30 FPS I would see less pausing or stuttering if some event happens to cause a jump in FPS.

aaah I see, stabilising the FPS would somehow increase performance, I suppose it makes sense, interesting! :)

You can argue whether its a really fix or it just fools your eye because the eye cant detect the smaller jumps, in my head it seems to help :) Try it out...