GENERAL SECTION
What is NVIDIA® SLI™ technology? How does it work?
How is SLI technology different from competitive product offerings?
Do you have dedicated hardware for SLI technology or is it just software?
How much of a performance increase will I see with SLI technology?
How does this technology differ from 3dfx's SLI technology?
Does SLI technology work on AGP?
How does SLI technology work on PCI Express?
What graphics cards support SLI technology?
What is the function of the SLI connector?
SLI FEATURE SUPPORT
What operating systems are supported with SLI technology?
What applications are supported with SLI technology?
Which driver should I use?
Why don't all games see performance increases?
What is SLI antialiasing?
Is NVIDIA working with Developers on SLI application support?
How many monitors are supported when running in SLI mode?
How do I switch from using two or more monitors in 2D/single-GPU mode to one monitor in SLI mode?
Can I output to my TV or HDTV in SLI mode?
What are the SLI Visual Indicators?
Can I use Coolbits for overclocking AND the expanded SLI functions?
What operating systems does 3-way NVIDIA SLI support?
CONFIGURATION SECTION
What motherboards support SLI technology?
What graphics cards support SLI technology?
Can I mix and match graphics cards?
Can I mix and match graphics cards if one of them is overclocked by the manufacturer?
Can I mix and match graphics cards with different sizes of memory?
Do other graphics card features such as VIVO need to match?
Can SLI technology work with one PCI Express board and one AGP 8X board or with PCI Express and PCI?
Can I install just one SLI-Ready graphics card in an NVIDIA nForce® SLI-based motherboard?
Where can I purchase an SLI connector?
What power supply does NVIDIA recommend for an SLI system?
Can I use more than two graphics cards in an SLI configuration?
Does SLI technology also work with three GPUs?
Where can I get a 3-way SLI connector?
Do I need a new power supply if I am building a 3-way SLI PC?
When I configure two GPUs in SLI mode, do the GPUs work together to create double the memory size of a single GPU?
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 nForce® SLI media and communications processor (MCP).
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 NVIDIA nForce® SLI 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.
How does this technology differ from 3dfx's SLI technology?
NVIDIA SLI technology differs in many ways. First, 3dfx’s SLI technology was implemented on a shared bus using PCI. The PCI bus delivered ~100MB/sec. of bus throughput, while PCI Express is a point-to-point interface that can deliver ~60x the total bandwidth of PCI. Second, 3dfx’s SLI technology performed interleaving of scan lines, and combined in the analog domain, which could result in image quality issues due to DAC differences and other factors. 3dfx Voodoo technology also only performed triangle setup, leaving the geometry workload for the CPU. This meant 3dfx’s SLI technology only scaled simple texture fill rate, and then used inter-frame scalability. NVIDIA SLI technology is PCI Express based, uses a completely digital frame combining method that has no impact on image quality, can scale geometry performance, and supports a variety of scalability algorithms to best match the scalability method with application demands.
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?
The list of SLI-Ready GPUs can be found here. A complete list of certified SLI-Ready graphics can be found here.
For information about SLI technology for NVIDIA Quadro graphics solutions, click here.
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. The SLI connector is not used with some mainstream graphics cards. These graphics cards pass inter-GPU data through the PCI-Express bus, instead of through the SLI connector. For these mainstream GPUs, there is enough excess bandwidth across the PCI Express bus to effectively manage this additional communication. More powerful GPUs require the SLI connector to achieve optimal scaling results.
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
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 www.nvidia.com.
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 1024x786 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 or SLI16x antialiasing and enhance the visual quality of any gaming application.
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. Please note SLI Antialiasing is currently not available on Windows Vista operating systems.
Is NVIDIA working with Developers on SLI application support?
Yes. NVIDIA is actively working with developers and educating them so that their titles can benefit from SLI technology as much as possible. By developing future titles on SLI technology, game developers are able to optimize their application for SLI configurations. Additionally, the performance of SLI technology today gives developers a glimpse of how tomorrow's single GPU systems will perform. This allows them to tune for all elements of the system including CPU utilization. See what the developers are saying about SLI technology here.
How many monitors are supported when running in SLI mode?
When in multi-GPU mode, SLI currently supports one monitor. When in single-GPU mode, users have the ability to use all of the connectors on their GPUs to connect to monitors using NVIDIA® nView® multi-display technology and Windows built-in multiple display support.
How do I switch from using two or more monitors in 2D/single GPU mode to one monitor in SLI mode?
You can switch between these modes by enabling or disabling SLI technology in the 'NVIDIA Control Panel’ (right-click on your desktop to open). With Release 80 graphics drivers, this switch no longer requires a restart of your PC.
Can I output to my TV or HDTV in SLI mode?
Yes. GeForce 6, 7, and 8 series SLI configurations support HDTV modes. However, GeForce 6 and 7 GPUs are limited to only support HDTV progressive modes with SLI enalbed (480p, 720p, and 1080p). For more information on the limitation on GeForce 6 and 7 series, please read this NVIDIA Knowledge Base article
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: two GPU SLI will over “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)
Can I use Coolbits for overclocking AND the expanded SLI functions?
With Release 90 or later ForceWare graphics drivers, Coolbits is no longer required for advanced SLI functionality. However, users can still use Coolbits to enable graphics cards with different memory sizes to work together in SLI mode. To enable this feature, along with overclocking functionality, set Coolbits to 1A.
What operating systems does 3-way NVIDIA SLI support?
3-way SLI will only be supported on the Windows Vista operating system. This includes 32-bit and 64-bit versions.
What motherboards support SLI technology?
The full list of certified NVIDIA nForce SLI-based 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 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?
In order to provide optimal symmetric scaling, SLI technology requires the NVIDIA GPUs to match. For example, a GeForce 7800 GTX must be paired with another GeForce 7800 GTX. Likewise, a GeForce 6600 GT must be paired with another GeForce 6600 GT. However, using the latest Release 80 or later graphics drivers, NVIDIA GPUs sold by different manufacturers can be used together in an SLI configuration. For example, a GeForce 7800 GT from vendor ABC can be matched with a GeForce 7800 GT from vendor XYZ.
Can I mix and match graphics cards is one of them is overclocked by the manufacturer?
Yes. A GeForce 7800 GTX that is overclocked (for example BFG GeForce 7800 GTX OC) can be mixed with a standard clocked GeForce 7800 GTX.
Can I mix and match graphics cards with different sizes of memory?
While it is not recommended, NVIDIA does offer this flexibility using Coolbits. When purchasing a second graphics card, you should try to match the memory size so that you are ensured full value and performance from your purchase. For example, if your first card is a GeForce 6600 GT with 128MB of memory, you should purchase a second GeForce 6600 GT with 128MB of memory. However, using Coolbits (value set to 18), you can force both of the cards to use the lower of the two memory sizes and operate together in SLI mode. When dissimilar memory sizes are enabled to work together using Coolbits, the effective memory size for each card becomes the smaller of the two memory sizes. Instructions to enable this feature can be found here.
Do other graphics card features such as VIVO need to match?
No, you only need to match the NVIDIA GPUs (for example GeForce 7800 GTX) for SLI technology to work. As mentioned above, NVIDIA also recommend that customers match the memory size to ensure that they get full performance and value out of their graphics card purchase.
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 NVIDIA nForce SLI-based motherboard?
Yes, NVIDIA nForce SLI-based 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 PCI-Express graphics card and motherboard. Always look for the SLI-Ready logo on certified components.
Where can I purchase an SLI connector?
The SLI connector is included with all NVIDIA SLI-Ready motherboards and with all SLI-Ready PCs. If your motherboard supports SLI technology and did not come with this connector, please contact the manufacturer of your motherboard or PC to obtain an SLI connector. Users with an nForce 680 motherboard that want to upgrade to 3-way NVIDIA SLI and do not have a connector can purchase the 3-way NVIDIA SLI connector from approved partners. Please visit http://www.slizone.com/object/slizone_3waysli.html for information on where to purchase these connectors.
SLI connectors for NVIDIA Quadro graphics cards:
SLI connectors for SLI-Ready NVIDIA Quadro-based systems can be purchased from your workstation manufacturer. The following workstation manufacturers provide SLI Ready systems:
HP Workstations
Sun Microsystems
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. More information about power supply selection can be found here.
Does SLI technology also work with four GPUs?
Yes. Quad SLI technology supports four GPUs in SLI mode. Learn more about Quad SLI technology here.
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. Learn more about 3-way NVIDIA SLI technology here.
Where can I get a 3-way SLI connector?
For users that have an existing nForce 680i motherboard that need a 3-way SLI connector, there will be several partners offering the connectors for sale. Please check this website for more information http://www.slizone.com/object/slizone_3waysli.html
Do I need a new power supply if I am building a 3-way SLI PC?
3-way SLI requires a power supply that means the total power requirements and has six PCI-E 6-pin power connectors. Please visit the Certified SLI power supply section on SLIZone.com
When I configure two GPUs in SLI mode, do the GPUs work together to create double the memory size of a single GPU?
In SLI mode, each graphics card uses its own framebuffer memory to render a 3D application. The operating system will report a graphics card framebuffer memory size that is found on a single graphics board.
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