Nvidia Forceware Tweak Guide

[Page 7] Forceware Control Panel (Pt.2)

Set PhysX Configuration

This section allows you to configure the use of PhysX advanced physics processing. Nvidia has incorporated GPU-accelerated PhysX capabilities into all CUDA-ready GPUs - specifically that means all GeForce 8 and newer cards with 256MB or more of onboard memory; previously PhysX effects were only possible when using a standalone Ageia PhysX PPU. PhysX is only of benefit in games and software which support its use, such as those listed here. The use of PhysX allows more realistic physics-based effects in supported games, but depending on the specific models of your GPU and CPU, you may get higher or lower performance as a result.

Note that to successfully use GPU-based PhysX you should install the latest Forceware drivers (i.e. 177.83 Forceware or newer), and the latest PhysX drivers (i.e. 8.08.01 or newer) - the PhysX drivers are now incorporated into the Nvidia driver package, so you do not need to download and install them separately.

Click to enlarge

The PhysX options in the 'Set PhysX Configuration' section of the Nvidia Control Panel are as follows:

  • Auto-Select - This allows the driver to automatically determine whether to select your GPU or CPU for processing PhysX effects. This is the recommended setting, as in most cases the drivers should be able to determine based on your GPU model(s) and CPU specifications which hardware to use for processing PhysX for optimal performance.

  • [GPU Name] - If selected, this option allows you to force PhysX processing onto a specific Nvidia GPU on your system. Use this if you want to experiment to see if shifting PhysX load to a particular GPU on a multi-GPU system can improve your performance.

  • CPU - If selected, this option forces all PhysX processing to occur on your CPU, which is the default for systems which don't have an Nvidia GPU, and essentially turns GPU-based PhysX off. This may help performance if you have a low-end GPU and a high-end CPU for example, or for particular games which are so strenuous on your GPU that offloading the PhysX processing to the CPU can improve overall performance.

  • Depending on the option you select, the diagram displayed in this section will change to show which of your display(s) is utilizing what form of PhysX. In general I recommend choosing 'Auto-select' as this will allow the drivers to determine the best processing hardware on your system to use for any supported PhysX effects. Advanced users can then experiment on a game-by-game basis to see if forcing PhysX onto a specific graphics card or even shifting the load to the CPU improves their overall performance. Also keep in mind that the 'CUDA - GPUs' setting in the Nvidia Control Panel (as covered on the previous page) determines whether PhysX is allowed to be used on a particular GPU on your system, as PhysX is a CUDA-reliant process.

    To see if PhysX is correctly enabled and being used in a game, you can enable a PhysX Visual Indicator by selecting the setting of the same name under the '3D Settings' menu at the top of the Forceware Control Panel. When PhysX is available in a game, a simple indicator will show whether it is running on the CPU or GPU while playing that game.

    If you don't have a PhysX-capable game to test and utilize the capabilities of GPU-based PhysX, you can download one of the free GeForce Power Packs which contain a range of demos and games that further demonstrate GPU-based PhysX effects. You can also view a range of PhysX videos on the main PhysX Site if you just want to see the types of effects which PhysX is capable of. When PhysX is enabled in a game which supports it, you will see enhanced physics effects such as additional debris, more detailed explosions and smoke (particle effects), greater destruction of the environment, better physics animations on objects, better water effects, improved cloth and paper effects, and so forth. However it is important to note that although GPU-based PhysX makes these additional effects possible with improved performance in many cases, in some cases it may also result in reduced framerates. What is happening is that your GPU is carrying an extra workload in calculating these additional physics effects, and depending on the game, your GPU, and the rest of your system, the FPS impact can be noticeable.

    The bottom line is that for a system with a single PhysX-capable GPU, in some cases you will see a noticeable FPS rise, in other cases you may see a noticeable FPS drop. It all depends on whether the additional PhysX effects are set to be always on in the game, or whether they can be enabled or disabled. Furthermore the degree to which your FPS increases or falls also depends on how powerful your GPU is compared to your CPU. If you have a high-end CPU and a low-end GPU for example, then shifting the PhysX load to the GPU may have a negative impact overall.

    On systems with multiple PhysX-capable Nvidia GPUs the story will be different - particularly on a non-SLI setup where you can set your most powerful Nvidia GPU as the primary graphics card, and add a second weaker Nvidia GPU and set it to just process the PhysX effects. In such a scenario you should usually get the benefit of both optimal FPS and additional PhysX effects. So for example if you have an unused GeForce 8 PCI-E card, you can slot it into a spare PCI-E port and utilize it for faster GPU-based PhysX in Multi-GPU (not SLI) mode.

    In any case by default since most games do not support PhysX, this setting has no impact on performance or image quality. Even in games which do support PhysX, the 'Auto-select' option should be optimal unless you are troubleshooting or experimenting. Some games also allow you to adjust the level of PhysX effects within the in-game settings.


    As noted on the previous page, this section may be in a category of its own, not under the 3D Settings category, if you've installed the nTune or System Tools Utility. Furthermore you can also enable a hidden Overclocking setting in this section - see the Overclocking chapter for details. The performance options won't be covered in this guide in detail, as technically they are not part of the regular Forceware Control Panel. Indeed you can access all the features in this section such as temperature monitoring by using GPU-Z and other handy free utilities listed in the TweakGuides Tweaking Companion.


    This section has settings which affect the way the image is displayed on your screen.

    Change Resolution

    This section allows you to change the screen resolution, color quality and refresh rate. These are detailed in the Windows Control Panel section of this guide and have exactly the same functionality.

    Adjust Desktop Color Settings

    This screen allows you to customize the brightness, contrast, vibrance and color balance of images on screen. Once you've selected the applicable display, for the second step ('Choose how color is set'), I recommend selecting the first option, which is 'Other applications control color settings' - this allows any application to set it owns colors if it needs to, which is usually best. If at any time you wish to override them and manually force your own color settings, select the 'Use Nvidia Settings' option. You can then adjust the various settings as covered below, and at the very least these will impact on the normal Windows Desktop:

    Color Channel: This drop down box lets you specify whether you want the changes you make on this screen to only be applied to a specific color, or to all colors. There is no reason to change this from its default of 'All Channels'. If for some reason you want to alter a particular color channel, for example if you want to make reds on your desktop a little brighter, select the Red color channel from the box. Now move the Brightness slider slowly to the right. You will notice that all reds on the screen will become brighter. This is useful for compensating for the way some displays over-represent a particular color by default.

    There are a range of sliders you can select under the Slider tab here, or if you are more advanced you can use a graph to change the color curve. The Sliders are recommended to all but the most advanced users. Note that there are several images you can use to judge the impact of your changes while calibrating your settings here - click the 1, 2 or 3 options under the image to the right to select a different calibration Preview Image.

    Brightness: This slider determines the overall level of light or dark for the display. 50% is the neutral and default point. You should ideally adjust your monitor's Brightness setting first if you feel it is too dark, then use this slider for fine tuning as required.

    Contrast: This slider determines the difference between light and dark. The higher the contrast the whiter whites will be and the darker blacks will be in relation to them. Some display types actually benefit from a slight reduction in contrast as this reduces glare and harshness, while others require a slight increase in contrast to reduce a muddy washed out greyness. Set to suit your taste.

    Gamma: This slider determines the brightness and richness of most images, but in a more subtle way than Brightness. It requires a bit more experimentation to reach an appropriate level which does not result in a washed out screen image, but also doesn't make the screen look too dark.

    The settings in the third step ('Apply the following enhancements') apply to all 2D and 3D graphics regardless of their own settings, so be aware that changing them will affect all your graphics:

    Digital Vibrance: This slider can increase color richness in an image so that all images - including 2D, 3D, as well as video - appear brighter and more colorful. The use of Digital Vibrance depends on your particular tastes and your particular display device(s). For most people I recommend only a slight increase if you want to use this slider, otherwise colors will appear neon bright and highly unnatural. There is no performance impact from using Digital Vibrance, so experiment to find a color level which suits you - you can see the impact of any changes immediately on your Desktop and in your games, as well as on the three reference images available on the right side of this section of the Control Panel.

    Hue: This setting controls the overall hue of colors, namely how correct they appear and the general tone of colors the image on screen appears to take. In general it shouldn't be altered as it can make colors completely inaccurate. If you find your monitor's color is too warm, or too blue-tinged, or too pale, or some other color-related issue, then consider changing the monitor's own settings, particularly the 'Color Temperature' (or similar) setting.

    Once done adjusting these, click the Apply button to save them.

    Rotate Display

    This section allows you to rotate the onscreen image through a series of preset angles. If you want to rotate the onscreen image through a set angle of either 90 degrees right or left, or 180 degrees (upside down), use one of the relevant options at the bottom of this box. Alternatively you can use one of the small arrow icons to the left and right of the small screen representation, or the one inside it. Once you've chosen the angle of rotation you require, click the Apply button and the change will be immediately visible. Note that only games or 3D applications which support rotation will work in rotated modes. Also note that rotation requires additional video memory, and as such if you have one or more displays rotated, you may experience reduced performance.

    View HDCP Status

    HDCP is the High-Bandwidth Digital Content protection system designed to ensure that copyrighted content streamed over a digital connection cannot be altered or copied without permission. This section allows you to see if your graphics card, digital connection, OS and monitor all support HDCP. If you see the fact that your graphics card and display are HDCP capable, you will be able to view HDCP-protected content such as Blu-Ray movies. If they are not HDCP capable you may not be able to play back such content or may face certain restrictions. Check your hardware specifications and cabling to ensure they all comply with HDCP requirements. see the Digital Rights Management section of the Windows Media Player chapter of the TweakGuides Tweaking Companion for more details.

    Adjust Desktop Size and Position

    If you have a digital flat panel - most commonly an LCD display - connected via a digital connection like DVI or HDMI, then this section allows you to determine how images at various resolutions appear on your screen. Basically since any digital flat panel display consists of a fixed number of separate pixels, it has a 'native' resolution at which images display at their sharpest. This native resolution (e.g. 1920x1080 which is the 'Full HD' standard) is the number of pixels in width x number of pixels high in the panel, and any time your software resolution is different to this native resolution (e.g. when a movie or game is using a different resolution) the image can be rescaled in one of the following ways depending on your choice:

  • Aspect Ratio: The image is rescaled to fill as much of the screen as possible, while also maintaining its aspect ratio. This ensures that the image will not appear distorted (squashed), but can result in black bars appearing around the image if its aspect ratio is different to that of your screen. It may also result in a reduction in image quality and crispness due to rescaling.
  • Full Screen: The image wil be stretched out to fill the entire screen. Where the image's aspect ratio is different to your screen's aspect ratio, the image may appear distorted, however no black bars will appear. It may also result in a reduction in image quality and crispness due to rescaling.
  • No scaling: The image will be displayed at its original resolution and aspect ratio, with no expansion or distortion through rescaling. This results in the most accurate and crispest image, but if the image's resolution is not identical to your screen's, then it will sit in the center of your screen with black bars/borders around it.

  • In general the 'No Scaling' option is recommended for the most accurate image when gaming, but if you do wish to scale/expand a lower resolution image to fill as much of your screen as possible (e.g. a DVD movie on an HDTV), then I recommend selecting the 'Aspect Ratio' option so that the image is not distorted (squashed horizontall or vertically).

    Perform Scaling on: This setting determines whether any rescaling of a lower resolution image is done by your graphics card's scaler (GPU) or your monitor's scaler (Display). If you have an expensive high-end monitor or HDTV, try selecting Display to see if it improves the quality of scaled images. Otherwise usually the scalers in the average desktop LCD monitor is not as good as those in a high-end graphics card, so the GPU option is recommended for most people.

    If you find that certain games or programs are not adhering to your scaling choices as covered above, you can tick the 'Override the scaling mode set by games and programs' box to attempt to force your preferred scaling to their image output.

    To preview the way in which images of different sizes (resolutions) will be scaled based on your settings, select a Resolution from the drop-down box under the Preview section here, and in the preview window you will see how such an image would look on your display. What the preview can't really show you is the quality impact of scaling - again, any image which is rescaled from its original resolution will display quality degradation, usually in the form of some softening and bluriness.

    Size: Under the Size tab you can fix images which are not being displayed properly, such as on TVs or monitors which apply overscan - i.e. the edges of the image go beyond the borders of the display.

    Set up multiple displays

    If you have two or more display devices connected to system, this section allows you to configure how they are used.


    The settings under this section only apply to video and TV playback on your PC. They do not affect your Desktop or games. Therefore it's recommended that you play a video while adjusting these settings to see the impacts of any changes you make.

    Adjust Video Color Settings

    You can choose whether to adjust video playback settings using the settings in your default media player, or select the 'With the Nvidia Settings' option to allow access to a range of settings which can override the media player:

    Color: The sliders under this tab include Brightness, Contrast, Hue, and Saturation. Most are already described above, but to add to these descriptions, the Hue slider determines the particular shade that colors take, while Saturation determines the richness of colors.

    Gamma: You can adjust the overall gamma using the top slider, or if you select the second option, you will then have access to separate Red, Green and Blue sliders you can use to individually adjust colors to correct any color flaws or over/under saturation of a particular color on your screen, or certain video sources.

    Advanced: Under this section, there is a Dynamic Range setting which can be accessed if 'With the Nvidia Settings' option is selected. You can switch between Limited and Full range, and the setting will affect the richness and detail in dark scenes. The 'Full (0-255)' setting should be optimal for seeing greater detail in blacks, but experiment to see how it looks on your display.

    Adjust Video Image Settings

    This section provides additional video playback image enhancement/adjustment options:

    Edge Enhancement: Here you can set the level of 'Edge Enhancement', which is a form of image sharpening that can help make blurry videos seem sharper. It can however also increase ghosting, so it needs to be used in minimal amounts.

    Noise Reduction: The 'Noise Reduction' slider can be used to remove film grain and other forms of 'visible noise' in the image, but can make the picture appear more blurry as a result.

    When done, click the Apply button, and once again, these changes only apply to Video/DVD playback.

    There will be other settings under this section depending on the device you've hooked up to your graphics card. They cannot all be covered here, most should be self explanatory.

    The next page looks at the nView functionality of the Nvidia Control Panel under Windows XP.