SLI Bridge



Technology and Configuration

SLI Bridge

What is the function of the SLI connector?

The SLI connector is a proprietary link between GPUs that transmits synchronization, display, and pixel data. The SLI connector enables inter-GPU communication of up to 1GB/s, consuming no bandwidth over the PCI Express bus.

Where can I purchase SLI connectors for 2-way, 3-way, or quad SLI?

SLI connectors are included with all NVIDIA SLI-Ready motherboards and with all SLI-Ready PCs. If your motherboard supports SLI technology and did not come with these connectors, please contact the manufacturer of your motherboard or PC to obtain them. If you need to purchase an SLI connector as a replacement or as an upgrade to 3-way SLI for an existing nForce 680i motherboard, users can find the connectors for sale on SLI motherboard partner websites.


What is SLI Antialiasing?

SLI Antialiasing is a new standalone rendering mode that offers up to double the antialiasing performance by splitting the antialiasing workload between the two graphics cards. When enabled, SLI Antialiasing offers two new antialiasing options: SLI8x and SLI16x. A Quad SLI system is capable of SLI32x. In the current driver, this rendering mode can be enabled by following these quick instructions. More information about SLI Antialiasing can be found here.


How many monitors are supported when running in SLI mode?

With GeForce R180 drivers (or later), standard SLI configurations for 2-way, 3-Way, and quad SLI support a maximum of two monitors. Additional monitors (up to 6 monitors total enabled) may be enabled by using either a motherboard GPU and/or a PhysX capable graphics card (GeForce 8 series or higher with at least 256MB of memory) that does not have the same GPU as those that are SLI enabled. More information regarding multi-monitor in SLI can be found here.

Can I use SLI multi-monitor in all SLI configurations?

Yes. SLI Multi-monitor is supported in 2-way, 3-way, and Quad SLI configurations and is enabled automatically when SLI technology is enabled in the 'NVIDIA Control Panel’ (right-click on your desktop to open).

Can I add a 3rd graphics card in my 2-way SLI enabled PC to connect more monitors?

Yes, you can add an additional graphics card to your PC to connect two additional monitors. The additional graphics card must have a GPU that is different from your SLI GPUs and must be NVIDIA PhysX capable (GeForce 8 series and higher with at least 256MB of memory). For example, two GeForce GTX 2XX GPUs in SLI and a GeForce 9XXX GT is a supported configuration.

Can I run my 3-way SLI configuration as 2-way SLI, connect two monitors, and then use the third graphics card that is not in SLI to connect two additional monitors?

No. A PC containing three graphics cards with the same GPU can only be run in 3-way SLI.

What is the SLI focus display and what does it do?

The SLI focus display allows you to select which monitor will receive the maximum SLI 3D acceleration for full screen 3D applications. In SLI multi-monitor mode, all monitors have 3D acceleration but only one monitor has maximum SLI 3D acceleration.

How do I change the SLI focus display?

The SLI focus display can be configured in three ways: 1) Assigning the primary monitor from the Windows Vista Display Properties Control Panel, 2) assigning the primary monitor from the NVIDIA Control Panel > Set up multiple displays page, or 3) selecting the SLI focus display for the NVIDIA Control Panel > Set SLI configuration page.

Are the SLI visual indicators going to change with SLI multi-monitor enabled?

Yes, the SLI visual indicator will change, but only for the SLI focus display. There will be a small green square that appears to indicate the SLI focus display. It will not change on any other modes or monitors.

Does SLI multi-monitor now support Clone mode??

Yes, clone mode is supported, but the 3D performance on both monitors will be less than the SLI focus display’s performance when in Dual View mode.

When you are running a full screen 3D application with the SLI focus display, what happens to the second monitor?

When running a full screen 3D application, the operating system and the application determine what happens to the second screen. The screen may go black or change resolutions to match the primary monitor. In addition, full screen applications prevent you from moving using your mouse and keyboard on the second monitor.

Can I render my 3D game full screen on more than one monitor?

Yes, a 3D game can be rendered full screen on more than one monitor if it is a multi-monitor aware game, such as Flight Simulator X. However, SLI multi-monitor will not let you render standard single monitor applications across multiple monitors.

Does SLI multi-monitor support GeForce 6 and 7 series?

No, currently SLI multi-monitor mode is only available for GeForce 8 series GPUs and above on Windows Vista and Windows 7 operating systems.

Technology and configuration

What is NVIDIA® SLI® technology? How does it work?

NVIDIA SLI technology is a revolutionary platform innovation that allows you to intelligently scale graphics performance by combining multiple NVIDIA graphics solutions in a single system with an NVIDIA SLI-Certified motherboard.

How is SLI technology different from competitive product offerings?

SLI technology is the only multi-GPU solution that was built from the ground up with dedicated scalability logic in each GPU. This logic enables the most efficient communication between GPUs providing the best scalability performance. SLI technology also has the most comprehensive list of supported games.

Do you have dedicated hardware for NVIDIA SLI technology or is it just software?

Yes. NVIDIA GPUs combined with an SLI®-Certified motherboard (which ships with the proprietary NVIDIA SLI connector) are the necessary building blocks for the SLI platform. Dedicated scalability logic in each GPU and a digital interface between GPUs (the SLI connector) enable this logic. In addition, a full software suite of advanced rendering algorithms provide the best image quality.

How much of a performance increase will I see with SLI technology?

The amount of performance improvement will depend on the application and its ability to scale. Several of today's hottest games see a full 2x increase in performance when using SLI technology with two graphics cards. 3-way NVIDIA SLI technology enables up to 2.8x performance increase over a single GPU. In general, applications running at higher resolutions with higher image quality settings will benefit most.

Does SLI technology work on AGP?

No. SLI technology is designed for PCI Express.

How does SLI technology work on PCI Express?

SLI technology is designed for PCI Express. This new bus has superior bandwidth (two to four times AGP 8X), support for isochronous data transport, and the capability to drive multiple high-speed graphics devices. AGP 8X is limited to one high-speed graphics device and was not a good candidate for SLI technology.

What graphics cards support SLI technology?

A complete list of certified SLI-Ready graphics cards can be found here.

What operating systems are supported with SLI technology?

SLI technology supports the following operating systems:

  • Windows XP 32-bit
  • Windows XP 64-bit
  • Windows Vista 32-bit
  • Windows Vista 64-bit
  • Windows 7 32-bit
  • Windows 7 64-bit
  • Linux 32-bit
  • Linux 64-bit (AMD-64/EM64T)

What applications are supported with SLI technology?

SLI technology can be enabled for every gaming application, including both OpenGL and Direct3D gaming applications. SLI technology provides either 3D performance scaling using alternate frame rendering (AFR) or split-frame rendering (SFR) or increased visual quality using the SLI Antialiasing mode. In order to provide the optimal 'out-of-box' experience for its customers, NVIDIA has created an extensive set of optimized game profiles which enable SLI scaling automatically. The full list of these SLI-optimized games can be found here. For applications not found in this list, simply follow these quick instructions to set up a new game profile to enable SLI technology. Information about professional application support can be found here.

Which driver should I use?

NVIDIA® ForceWare® Unified Driver Architecture (UDA) supports SLI technology. Simply download the latest GeForce or Quadro graphics driver from the driver download page located here.

NVIDIA continually adds new SLI applications profiles to upcoming drivers. For the most up-to-date SLI application support, always use the latest drivers.

Why don't all games see performance increases?

Applications which tax the GPU will see tremendous performance improvements of up to 2x with SLI technology when using two graphics cards. Most of today's hottest games and as well as next-generation games fall into this category. However, some applications, typically older generation applications, are limited by factors other than the GPU's processing power.

The most common limitation is the CPU. If an application becomes CPU bound, no additional graphics power can improve performance. This situation is most common at low screen resolutions like 1024x768 with no additional functionality turned on. Turning on antialiasing and anisotropic filtering or switching to higher resolutions can often move the processing requirements back to the GPU.

For CPU-bound applications, NVIDIA offers a new SLI rendering mode called SLI Antialiasing. This rendering mode allows you to enable SLI8x, SLI16x, or SLI32x (for quad SLI only) antialiasing and enhance the visual quality of any gaming application.

What are the SLI Visual Indicators?

If you see horizontal or vertical green lines on your screen (shown here), it means that you have "Show SLI Visual Indicators" enabled in the NVIDIA Display control panel. When enabled, this option shows how your GPUs are sharing the graphics load and will overlay the name of SLI in your system: 2-way SLI will overlay “SLI”, 3-way NVIDIA SLI will overlay “SLI x3”, and Quad SLI will overlay “Quad SLI”. For games that are rendered using alternate frame rendering (AFR), a green vertical bar will grow up and down on your screen, depending on the amount of scaling. For games that are rendered using split-frame rendering (SFR), a green horizontal line will move up and down on your screen, showing how the load is being balanced between each GPU. If the upper half and the lower half of the screen have a similar level of detail, the horizontal line will stay close to the middle. To enable or disable this feature, simply open the NVIDIA Control Panel and select 3D Settings. With the 3D Settings page open, click on the 3D Settings tab in the upper menu bar (shown here)

What operating systems does 3-way NVIDIA SLI support?

3-way SLI is currently supported on the Windows Vista and Windows 7 operating systems. This includes 32-bit and 64-bit versions.

What motherboards support SLI technology?

The full list of certified NVIDIA SLI-Ready motherboards can be found here. This list is updated frequently with new SLI-Ready components.

What graphics cards support SLI technology?

SLI technology is designed for PCI Express and not AGP. This new bus has superior bandwidth (two to four times AGP 8X), support for isochronous data transport, and the capability to drive multiple high-speed graphics devices. The full list of certified NVIDIA SLI-Ready graphics cards can be found here. This list is updated frequently with new SLI-Ready components.

Can I mix and match graphics cards that have different GPUs?

No. For example, an XXXGT cannot be paired with a XXXGTX in an SLI configuration.

Can I mix and match graphics cards from different manufacturers?

Using 180 or later graphics drivers, NVIDIA graphics cards from different manufacturers can be used together in an SLI configuration. For example, a GeForce XXXGT from manufacturer ABC can be matched with a GeForce XXXGT from manufacturer XYZ.

Can I mix and match graphics cards if one of them is overclocked by the manufacturer?

Yes. A GeForce XXXX GTX that is overclocked can be mixed with a standard clocked GeForce XXXX GTX.

Can SLI technology work with one PCI Express board and one AGP 8X board or with PCI Express and PCI?

No. SLI technology is designed solely for PCI Express.

Can I install just one SLI-Ready graphics card in an SLI-Ready motherboard?

Yes, SLI-Ready motherboards can support any single PCI Express-based graphics card, so you can always start with one card now and upgrade to a complete SLI configuration at a later time. For the best experience and upgrade potential, make sure to buy an SLI-Ready graphics card and motherboard. Always look for the SLI-Ready logo on certified components.

What power supply does NVIDIA recommend for an SLI system?

NVIDIA has extended its SLI-Ready certification program to include power supplies. The full list of SLI-Ready power supplies can be found here. In general, power supply recommendations vary widely depending upon the configuration and the desire for future upgradeability.

Does SLI technology also work with four GPUs?

Yes. Quad SLI technology supports four GPUs in SLI mode.

Does SLI technology also work with three GPUs?

Yes, this is called 3-way NVIDIA SLI technology and it supports three GPUs in SLI mode.

Do I need a new power supply if I am building a 3-way SLI PC?

Please visit the Certified SLI power supply section for a list of power supplies that will support your graphics cards in 3-way SLI.

When I configure two graphics cards in SLI mode, do the graphics cards work together to create double the memory size?

No. In SLI mode, each graphics card uses its own frame buffer memory to render a 3D application. The operating system will report a graphics card frame buffer memory size that is found on a single graphics board.