-=Warning Riva Tuner is a very powerfull application, please be cautious when using it=-
I first had this annoying problem when I switched from a CRT to an LCD last August. I'm not sure if the monitor type had anything to do with it or not but that's when it first seemed to appear.
So far I'm only aware of this working on Nvidia Based Cards.
My best description of the issue is that altho framrates are constant and smooth, (meaning the fps indicator would read xxx FPS yet the image on screen stuttered like crazy), I got a horrible stutter driving different mods on different tracks. When a highly detailed car was on the turntable on the ingame menu I got it too.The issue wasn't across the board and didn't seem to be resolved by any changes in my GFX detail settings, either ingame or in the driver control panel. For me it was worst and most noticiable on the F1 2005 Mod, and recently ther have been 5-7 cases of it on the Caterham Mod.
This is the first tutorial I've ever written so please pardon any poor grammar or confusing steps
1. Download and install Riva Tuner HERE
2. Start Riva Tuner, if need be, click on the "Main" tab at the top.
3. Find where it says "Driver Settings" in about the middle of the menu and click on the "customize" button, just to the right of where it says "ForceWare Detected" in the screenshot.
4. Click the 2nd icon in, ("Green X") that says "DirecDraw and Direct 3D Settings".
5. Click on the "Vsync" Tab.
6. Change the number where it reads "Prerender Limit" to 0. (mine and other's said 3, one guys said 80)
7. Click "Apply" and "OK"
8. Click "OK" one last time to close Riva Tuner.
9. Start rFactor and put a car on the turntable if there isn't one there already. Preferably one that used to stutter and see if it's now smooth.
10. Enjoy Stutter Free Driving