Can You Run Two Different Graphics Cards in SLI?

Having a graphics card is essential for a computer system, particularly for a gaming computer, as it significantly impacts the computer’s performance and visual capabilities. A graphics card or a GPU is responsible for rendering images, videos, and animations that are displayed on the monitor. While integrated graphics can handle basic graphics tasks, a dedicated graphics card is designed specifically for handling complex graphical computations, making it a crucial component for gaming and other graphics-intensive applications.

One of the primary reasons a graphics card is necessary for gaming is its ability to handle 3D rendering. Modern games feature increasingly complex and realistic graphics, including intricate textures, detailed models, and advanced lighting effects. To achieve smooth and immersive gameplay, a dedicated GPU is required to handle these demanding tasks efficiently. However, one can surely benefit from having 2 GPUs in a system instead of one. And it surely is possible with the help of SLI.

If you are not aware of SLI or looking to understand more about SLI, you have come to the right place. In this guide, we will learn about SLI technology and some important factors that you need to consider before you can prep your system for an SLI configuration.

What is SLI?

SLI stands for Scalable Link Interface, and it is a technology developed by NVIDIA for linking multiple graphics cards together in a single computer system. The primary purpose of SLI is to increase graphical processing power for demanding applications like gaming, 3D rendering, and simulations.

When two or more compatible NVIDIA graphics cards are connected via SLI, they work together to share the rendering workload, effectively doubling or tripling the graphical processing capabilities compared to using a single card.

The SLI technology works by dividing the rendering tasks between the connected GPUs. One card acts as the primary, and the others are supporting. The master GPU receives the graphical information from the CPU and divides the rendering workload into smaller tasks, which are then distributed among the supportive GPUs.

Each GPU renders a portion of the image, and the final result is combined to produce a seamless and high-quality display on the monitor. This distributed rendering process allows for smoother and more detailed graphics, especially in graphics-intensive applications that push the limits of a single graphics card.

It’s important to note that SLI support in games and applications is dependent on the developers. While many popular games and software are optimized to take advantage of SLI, not all titles may fully utilize multiple GPUs, and in some cases, SLI may even cause compatibility issues or performance inconsistencies. As a result, it’s essential to check the game’s SLI support or read reviews from other users before investing in a multi-GPU setup.

Is It Possible to Run 2 Different GPUs Using SLI?

To put it simply, no. The SLI technology requires the use of two or more identical graphics cards to work together in tandem. The graphics cards must be of the same model and from the same series. This is because SLI relies on a specific set of hardware configurations and software optimizations that are designed to work seamlessly when the GPUs are identical.

If you attempt to run two different graphics cards in SLI, the technology will not function as intended. Instead, the system will likely default to using only one of the graphics cards, effectively disregarding the other altogether. In some cases, having mismatched graphics cards in an SLI configuration may even cause system instability or compatibility issues.

However, it’s worth noting that NVIDIA’s modern multi-GPU technology has shifted away from traditional SLI, and now supports multiple different GPUs known as heterogeneous multi-GPU. It was introduced with DirectX 12 and Vulkan by Nvidia. This technology allows users to pair different graphics cards from the same GPU family to work together for improved performance in certain applications.

What are the Factors to Consider?

Before investing in SLI (Scalable Link Interface) for a multi-GPU setup, it is crucial to consider several important factors to ensure a cost-effective and optimal performance solution. SLI can be an enticing option for users looking to boost their system’s graphical processing power, but it is essential to weigh the advantages and disadvantages to make an informed decision.

1. Chipset

The chipset of your motherboard plays a crucial role in determining whether SLI is supported and to what extent. Not all motherboards are compatible with SLI, and even those that support it might have limitations on the number of GPUs that can be used in SLI mode. Before investing in SLI, ensure that your motherboard has the appropriate chipset and sufficient PCIe slots to accommodate the number of graphics cards you intend to use.

2. VRAM

Video RAM (VRAM) is the dedicated memory on the graphics card that holds textures, frame buffers, and other graphical data. When using SLI, the VRAM does not stack; instead, it remains the same across all linked GPUs. Therefore, the total VRAM available for the SLI setup is equivalent to the VRAM of a single graphics card. For graphics-intensive applications, especially at higher resolutions or when using multiple monitors, having sufficient VRAM is essential to avoid performance bottlenecks.

3. Motherboard

Beyond just the chipset, the overall quality and capabilities of your motherboard are essential for a smooth SLI experience. Ensure that your motherboard has robust power delivery and proper spacing between the PCIe slots to allow for adequate cooling of the GPUs. Additionally, some high-end motherboards come with SLI-certified features and components, which can enhance stability and performance in an SLI configuration.

4. CPU

The processor, or CPU, can also impact SLI performance, especially in CPU-bound scenarios. When using multiple powerful GPUs, having a capable CPU that can keep up with the graphics processing demands is essential. Bottlenecks can occur if the CPU cannot feed data fast enough to the GPUs, limiting their potential performance gains. To maximize the benefits of SLI, pair it with a suitable high-performance CPU.

5. Power Supply

SLI configurations demand more power than single-GPU setups. When adding extra graphics cards, you must ensure that your power supply unit (PSU) can handle the increased power requirements. A high-quality PSU with sufficient wattage and the necessary PCIe connectors is critical to prevent system instability or crashes due to inadequate power delivery.

6. Chassis Setup

The physical arrangement and airflow within your computer case are vital when running an SLI setup. Multiple GPUs generate more heat, and improper cooling can lead to thermal throttling and reduced performance. Ensure that your chassis has adequate airflow and that your cooling solutions can handle the extra heat generated by the additional graphics cards.

7. Drivers

SLI functionality depends on driver support from the GPU manufacturer. It is essential to keep your GPU drivers up to date, as new driver releases often include performance optimizations and bug fixes for SLI configurations. Moreover, some games may require specific driver profiles to enable SLI support effectively.

How to Use SLI?

1. Using Nvidia Geforce Drivers

The best option to enable SLI on Nvidia cards is through official Nvidia drivers. Here’s how you can set it up quickly using Nvidia’s drivers:

• Install the driver software on both computers.
• Use a PC-to-PC connection with an Ethernet cable or crossover cable.
• Link the two graphics cards together using a USB cable.
• Enable SLI on the primary graphics card and install the driver software on the second PC.

2. Using the Nvidia Control Panel

To enable SLI with two identical graphics cards, you can use the NVIDIA Control Panel, which is the simplest method. Here’s how you can do it:

• Open the NVIDIA Control Panel.
• Choose your primary graphics card from the drop-down menu.
• Select the card you want to pair with it.
• Click the “Enable SLI” button, and restart your PC for the changes to take effect.

You can also enable SLI Boost, which can provide a slight performance boost by disabling certain features on the primary card.

3. Using an Nvidia Control Panel With an SLI Bridge

On the other hand, if you prefer to use an SLI bridge, follow these additional steps:

• Purchase an SLI bridge that matches your graphics cards’ specifications.
• Install the SLI bridge to connect the two cards together physically.
• Then, follow the same steps as above in the NVIDIA Control Panel to enable SLI.

What are the Pros and Cons of SLI?

While there are numerous advantages of SLI, there are also a few drawbacks that you should be aware of before setting it up. Here are some common pros and cons of the technology:

Pros

• Increased Graphics Performance: The primary benefit of SLI is its ability to combine the power of two or more graphics cards, providing a significant boost in graphical processing power. This is particularly beneficial for gaming and other graphics-intensive applications, as it allows for smoother frame rates and improved visual quality.
• Enhanced Gaming Experience: SLI can deliver a more immersive gaming experience by enabling higher resolutions and detail settings. It allows gamers to enjoy the latest titles at their highest graphical potential, leading to a more captivating and realistic gaming experience.
• Future-Proofing: SLI can extend the life of your gaming rig. As newer, more demanding games are released, a single graphics card may struggle to maintain smooth performance. SLI enables users to keep up with the latest gaming trends without having to replace their entire GPU.
• Scalability: SLI offers flexibility in GPU configurations. Users can start with a single graphics card and later add another one to boost performance further. This scalability allows for incremental upgrades, allowing users to adjust their setup based on their needs and budget.

Cons

• Limited Game Support: One significant drawback of SLI is the variable game support. Not all games are optimized for SLI, and some may not support it at all. In such cases, the second GPU may not be utilized efficiently, resulting in no performance gain or even potential compatibility issues.
• Increased Power Consumption: Running multiple GPUs in SLI demands more power, requiring a higher wattage power supply unit (PSU) and potentially increasing electricity costs. The increased power consumption also leads to more heat generation, necessitating better cooling solutions.
• Heat and Thermal Concerns: SLI configurations can generate significant heat, especially when using high-end GPUs. Proper cooling solutions are essential to prevent overheating and thermal throttling, which can reduce performance and potentially damage the graphics cards.
• Higher Cost: Building an SLI setup can be more expensive than using a single high-performance GPU. It involves purchasing two identical graphics cards, an SLI bridge (if applicable), and a more substantial power supply, which can increase the overall cost of the system.

Graphics Cards in SLI – FAQs

Conclusion

SLI can surely improve performance in compatible games and applications, providing smoother frame rates and better visual quality. However, SLI also has some noticeable limitations such as limited game support and increased power consumption. New high-end GPUs can offer a more straightforward and reliable performance boost without relying on SLI compatibility. Upgrading to a new GPU may be more expensive in most cases, but it provides access to the latest technology and architectural improvements. The choice between SLI and a new GPU depends on your needs, budget, and application requirements. Along with that, you also need to consider factors like long-term viability and potential SLI support in future titles.