WARNING: Don't mess with these applications, they are powerful tools which if not used properly can damage your hardware. I don't take any responsibility for you messing your graphics card up! As long as you stick to these tutorials you will be fine.
RivaTuner Tutorial (NVIDIA GPUs)
Step 1 - Download RivaTuner
RivaTuner DownloadStep 2 - Install RivaTuner
Usual procedure, extracts to somewhere like your desktop. Then browse to the setup file and follow the wizard.Step 3 - Set up RivaTuner
First time you run the program you will have to wait for it sort itself out.Once this has completed you will get to the main RivaTuner screen.
Next, click the power user tab.
Then expand the "RivaTuner \ NVIDIA \ Global" menu. Enter a value in "LODBiasRange" of 15.
Go back to the main tab. Then click on the little arrow Under "Driver Settings" next to whe it says "ForceWare detected." Click on the directX Symbol to open a new window (Pink in screenshot below).
In the new window, adjust the slider to where you want it. Put it on 0 to turn off any changes (Application will decide the LOD). 15 will be worst textures.