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Can you use two different graphics cards in one computer?

How to use two different graphics cards in one computer?

Two different graphics cards will NOT operate in tandem to increase frame rate performance. If you’re a gamer wanting to increase frame rate performance. Sadly two different graphics won’t work.

A two different card setup is fine for day trading applications or general productivity tasks. Two cards used this way will provide additional monitor outputs. However all the graphical processing load for a single task is handled by the primary GPU only.

If you’re a CAD user then a different card setup can be used to assign different tasks to separate GPU. For example rendering using one GPU whilst modelling on the other.

Windows 10 allows users to select the primary GPU. Users can nominate the primary card then open an application. Set the second card as primary and run the second application. Two tasks can be run on separate GPU’s. Dedicating 100% of each GPU’s efforts to each task.

NOTE: Adding an additional GPU requires a compatible motherboard with an additional PCI express slot.

What is Direct X 12 Explicit Multi-Adapter

Several years ago the use of Direct X 12 Explicit Multi-Adapter by some gaming developers allowed two different graphics cards to add frame rate performance.

Explicit Multi-Adapter meant not having to choose between Nvidia or AMD graphics cards for gaming applications. It eliminated compatibility issues and provided excellent frame rate performance scaling.

But EMA became hard to implement for many developers and the idea never really caught on. Only a handful of games and applications support Direct X 12 EMA.

If you want to add frame rate performance by adding an addition graphics card. Your best option is to install compatible (identical) cards. Either both compatible Nvidia or AMD with SLI (Nvidia) or Crossfire (AMD) bridges. Or upgrade to a single more powerful GPU.


Do You Need to Have Same VRAM?

Ideally this EVGA 1060 3 GB would not be paired wi
Ideally this EVGA 1060 3 GB would not be paired with ASUS GTX 1060 6GB.

Ideally, YES! When getting graphics card for SLI, you should aim to get two with the same VRAM amount. Otherwise, while the SLI WILL work, it will operate with capacity of the lowest of the two.

For example, if you get an NVIDIA GTX 1060 3GB VRAM GPU and an NVIDIA GTX 1060 6GB VRAM GPU for your SLI setup, then while the SLI WILL work, it will only work at the reduced performance of 3GB each.

In other words, the VRAM will NOT add up here to 9 GB, instead, it will be brought down to 6 GB in total.

How to Install and Setup SLI

The actual physical installation of SLI is very simple, and just a matter of installing GPUs in the right slots and attaching the SLI bridge between them. The potentially difficult and time-consuming part is the software side of things, and getting certain games to run smoothly without issues such as visual glitches/micro-stuttering (even in games that do support SLI). 

For more exact detail on installing a SLI setup, see the video below, but here are the quick overall steps on how to set up SLI in a nutshell:

  1. Install GPUs into PCIe x16 slots on the motherboard, referring to the motherboard manual for guidance on which slots to install them in (and considering maximum airflow, too).
  2. Connect power supply PCIe connectors to all the graphics cards.
  3. Attach a SLI bridge on top of the cards.
  4. Connect the DisplayPort/HDMI cable to the card installed at the top of your motherboard
  5. Enable SLI in the NVidia control panel in Windows

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Preparing to power up for the first time

Before you power your system up for the first time in SLI or CrossFire, you need to quickly make sure that your installation is correct.

  • Confirm by inspection that both graphic cards are securely screwed into the appropriate slots on your case.
  • Insure that the power cables for the graphic cards are installed and that they are the correct kind of power connectors.
  • Insure that you have removed all surplice screws or other items that you used during the installation of the graphic cards.
  • Insure the bridge cable is connected properly at both ends.

Now you are ready to boot into the OS!

The Motherboard

Not all motherboards will allow a dual graphics card set up, make sure that your motherboard is compatible. An easy way to find that out is to simply go to the product page and check the specifications of your motherboard.

Or look on the box.

Is it worth using a dual GPU in 2021?

Sure, two graphics cards can offer you a great performance upgrade, but is it worth it to explore such an expensive concept, which also includes so many liabilities?

There is no cut and dry answer, but if you are willing to manage with the side effects and ACTUALLY need dual graphics cards running in tandem on your PC – it might be worth it.

If all things go as planned, you will have a dual-card setup resulting in higher framerates and an even higher ceiling of setting visuals as per your choice. Instead of replacing a card entirely, the addition of another graphics card means that you will also be getting enhanced performance, but the question you need to ask yourself is, do you really need it?

If you are a hardcore gamer, or your game runs across several displays, maybe at extreme resolutions, using dual graphics cards can greatly enhance your game speed and gaming experience. 

If you have incredibly intense editing demands, or you use a multi-monitor setup, using two graphics cards will surely benefit you.

However, if you are a regular OC user with regular, run-of-the-mill usage demands, we will definitely not recommend venturing into hooking two graphics cards on your PC.

SLI Modes

There are various types of SLI modes of operation which are being mentioned below:

Split Frame Rendering (SFR) – In this mode GPUs split the workload equally to render the image on the screen.

Alternate Frame Rendering (AFR) – In this mode one GPU renders odd frames and other GPU renders even frames alternatively.

SLI Antialiasing – In this mode two GPUs split the workload of Antialiasing to provide smoother and superior image quality without any jagged edges.

Hybrid SLI – In Hybrid SLI, discrete GPU (Graphics Card) and IGP (Integrated Graphics) work together to increase performance. It can be found on laptops too.

Important Note – You need a powerful CPU for high-end SLI configuration otherwise the CPU will be a bottleneck for the graphics cards and performance will suffer drastically.

Recommended: Best Kaby Lake Processors for Gaming

What You Need for SLI Compatibility

The Asus Rog Strix SLI HB bridge to connect multipThe Asus Rog Strix SLI HB bridge to connect multiple Pascal GTX 10 series GPUs

For SLI to work you will need the following things:

  • Two or more SLI-supported graphics cards of the same NVidia architecture (brands and styles can be mixed so long as they’re the same base GPU).
  • A compatible SLI bridge to physically connect your GPUs (explained later).
  • A motherboard that officially lists SLI compatibility in its specs.
  • Two available PCIe x16 slots on your motherboard that will run at x8 (ideally the full x16 lanes) with multiple GPUs installed. SLI is not supported if a slot runs at x4.
  • Sufficient airflow within your gaming PC case to accommodate for the extra heat generated by multiple cards, meaning having enough case fans, well-cooled GPUs, a high-airflow case design, and ideally water cooling your PC
  • A strong gaming CPU to avoid your GPUs being bottlenecked, especially if using monitors with high refresh rates of 100Hz and above as getting high frame rates isn’t just about graphics power.
  • Patience and understanding that SLI really is not for everyone and may disappoint when it comes to performance scaling and game support.


The primary disadvantage of running dual graphics cards is the cost. Top-of-the-line cards can cost $500 or more. While both ATI and Nvidia offer lower-priced cards with dual capability, you can spend the same amount of money for a single card with equal or better performance than two low-priced GPUs.

Another disadvantage is that not all games benefit from multiple graphics cards and some graphics engines do not handle two cards well. Some games may show a decrease in performance over a single graphics card setup. In some cases, stuttering makes the video game look choppy.

Graphics cards are power-hungry. Two graphics cards installed in a computer can double the amount of power required to run them in tandem. For example, a single high-end graphics card might require a 500-watt power supply to function properly; two of these cards may require 850 watts. Most consumer desktops aren’t equipped with high-wattage power supplies. Refer to the computer power supply wattage and requirements to determine if your system can run dual graphics cards.

The performance benefits of a dual-card environment vary depending on the other components in the computer system. Even with two of the highest level graphics cards, a low-end processor can throttle the amount of data the system provides to the graphics cards. Dual graphics cards are typically recommended only in high-end systems.

People who mine cryptocurrency often run massive banks of video cards because GPUs process blockchain transactions much more efficiently than a CPU.

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