What do you get when you combine two powerful GPUs in your rig? Logic dictates that you would get higher performance, better frame rates, and more room to max out your display settings, which is all true for the most part. However, combining two graphics cards doesn’t always produce better results than a single high-end card, especially if you use your computer for less demanding tasks.
Having two graphics cards is better than having one if you’re a professional user relying on your GPUs for resource-intensive tasks. Two compatible cards can divide the workload and create a better experience by bringing higher frame rates and 4K resolution.
Less than a decade ago, you would need more than one graphics card for heavy-duty applications and multi-monitor gaming.
Today, you only need one GPU for the optimal experience. In this article, I’ll explain why dual graphics cards were (technically) better than one, alongside the pros and cons of dual and single-GPU systems.
Are Two Graphics Cards Better Than One?
Before we dive any deeper, it is important to point out that dual graphics cards are, to some point, a thing of the past. Most games today do not support SLI (more on that later), and a single high-end card can easily beat two.
How do single and dual-GPU setups compare across their rendering capabilities and performance? Here’s a brief overview.
Your graphics card(s) are vital in creating the ultimate gaming experience. More game data means more detail, and more detail means higher-quality resolution.
Larger games store more content, including high-resolution assets and thousands of 4K textures. Having a setup that can process this data smoothly and efficiently makes sense.
As you may have guessed, single and dual-GPU setups are not equal in rendering capabilities. Getting multiple cards to split the load allows your system to render frames more quickly.
The result is a smooth game flow with enhanced performance on the average framerate.
Rendering happens in different ways on different GPUs. With one GPU on board, all the calculations are done by a single card, while on multiple cards, tasks are split in one of the following ways:
- Antialiasing. Antialiasing seeks to eliminate jaggies when your screen lacks the appropriate resolution to display smooth, clear lines. In antialiasing mode (AA), these tasks are performed by both GPUs, and the results are merged into a final frame.
- Alternate frame rendering. Here, frames are rendered so that the first GPU renders one frame while the second GPU renders the next frame. The result is GPU 1 works on frames 1,3,5,7… while GPU 2 works on frames 2,4,6,…
- Split frame rendering – As the name implies, split frame rendering splits one frame horizontally. Each GPU renders one piece of the split frame.
A single GPU, on the other hand, does all the rendering on its multiple cores. By sharing the work between different GPUs, it’s easy to see why dual cores would render faster than single cores. Theoretically, dual GPUs can render frames almost twice as fast as a single GPU.
Displaying large content calls for massive calculations, which one chip can comfortably handle independently.
Multi-GPU technology brought new benchmarks for in-game performance at the time with the aid of Crossfire and SLI technologies. But recently, game developers and GPU manufacturers have scaled back on their support for multi-GPU technology, partly due to the rising costs of game development.
However, dual GPUs are no longer encouraged by game developers. Other factors are easier to control and have an even more important effect on game performance. Some of these are:
- PCIe bus speed and the number of lanes it supports. This can interfere with the data transfer speed and affect performance indirectly. Tons of data must be transferred between the GPU and CPU. Your system must keep up with the transfer speed, and failure to do so leads to stuttering.
- Insufficient VRAM. The amount of VRAM on your GPU dictates how much of a workload it can handle. It’s essential for rendering top-quality images at a higher resolution. Simply put, VRAM means better performance. Signs of low VRAM include a significant FPS drop and low-quality images.
- Latency and bandwidth. These affect the transfer of data to and from the GPU. Here, latency significantly impacts the performance of a GPU when transferring small amounts of data, while large transfers are majorly affected by bandwidth issues.
Despite these limitations, two mid-range GPUs will most likely not beat a single great high-end graphics card. With that in mind, how do two graphics cards weigh against one?
Pros and Cons of Dual and Single-GPU Systems
Having two GPUs in your computer is often touted as providing a significant performance boost. While this isn’t as true as it was in the past, there are several things to be happy about when choosing a dual-GPU system.
Pros of Dual-GPU System
- More computing power. Two cards put out a lot of raw power for processing massive game data and rendering high-resolution graphics on your screen.
- Slightly better performance. Given the same hardware, dual-GPU systems tend to deliver slightly better performance. However, this is not always true for modern, high-end gaming systems, which can often push your PC’ to the limits. When upgrading from a single-GPU setup to a dual-GPU configuration, you can expect a slight performance boost.
- Higher frame rates. When two GPUs are combined in a dual-GPU system via SLI, they can render frames faster and more efficiently. Faster frame rates mean smoother gameplay.
Lastly, an extra graphics card means you’re always backed up with an extra GPU in case one gets damaged.
On the likely occasion that a second card doesn’t bring much difference to your gaming experience, simply uninstall it from your computer and store it well. It could come in handy when the primary card fails or when there is a shortage of decent GPUs on the market.
Cons of a Dual-GPU Setup
Although two graphics cards promise the world in higher frame rates and enhanced performance, they’re still plagued with several shortcomings that you need to be aware of before buying them for your PC.
Additional Hardware Is Required
Adding a second GPU is limited by the number of options at your disposal, i.e., you can only add the same GPU model as your existing GPU. What’s more, you need to bridge your cards with an SLI bridge, which is a physical connector that allows all the cards to function together.
Potential Incompatibility Issues
Unfortunately, not all games run effortlessly on two GPUs in an SLI/CFX setup. In fact, most modern games are better suited to a single, high-end graphics card. In many cases, two different cards may be compatible, but that depends on whether they’re from the same base model.
To ensure that your cards work together, your motherboard must support two graphics cards in the first place. Additionally, both cards must be compatible and support SLI or Crossfire (the technologies responsible for enabling multiple GPUs to split the load between themselves.)
Higher Power Consumption
More processing power means more energy will be drawn from the system. Most PCs today are not equipped with a powerful power supply that can support two or more GPUs at the time of purchase without being overworked. Instead, you will have to shell out more money on a more powerful high-end PSU.
Heat Management Issues
Heat management has always been a menace for custom PC building. A single GPU can turn much of the energy that goes into its functions into heat.
GPUs can operate comfortably between 104-194°F (40°C to 90°C), with higher-end models tolerating higher than 212°F (100°C). An overheating GPU is marked by heavily spinning noisy fans, unexplained lagging, and GPU failure.
With this much heat generated, you can imagine how much heat two GPUs stacked together would produce.
Your computer case, motherboard, and closeby CPU quickly turn hot, too, when in close proximity to the GPUs. When this happens, case fans may not be enough to deal with the issue. And even if they do, they may still bring another problem yet: unwanted noise.
For this reason, I recommend not putting two cards close to each other. Also, consider investing in liquid cooling with an external radiator. If you have too many tasks running simultaneously, you might want to close down the least priority ones to prevent overloading your GPU.
Other reasons why your GPUs overheat include the age of the computer and the condition of its cooling system, and that includes the state of the thermal paste.
High Cost of Purchase
If you plan on acquiring multiple GPUs, you must be prepared to cough up more money. A single high-end GPU cost can easily skyrocket in the hundreds. Two cards can go for thousands. The inevitable GPU shortages on the market also add to the high price tag.
Either way, the cost of a second GPU will depend on the card you choose. Generally, the more powerful and expensive the card, the more it’ll cost.
Pros and Cons of Single-GPU Systems
It’s only fair to compare the benefits and shortcomings of dual-GPU systems to those of single-GPU systems.
Pros of Single-GPU Systems
Single-GPU systems have remained dominant to date. It’s more convenient to install and manage a single card, it’s much less expensive, and the power consumption is more manageable. Here’s a brief breakdown of the top benefits of a single-GPU setup:
- Less power consumption. Generally, dual GPU setups require almost double the power it would take to run a single GPU. This can be a major setback if you’re using a system that doesn’t supply sufficient power. On the other hand, a single GPU consumes less power and is suitable for users who are not ready to spend more on replacing their power supply units.
- A cooler and quieter system overall. A single GPU will not draw nearly as much power as two GPUs. With less power comes fewer heat management issues, and the PC’s built-in fans would be enough to dissipate the heat faster and more efficiently. A reduced number of fans also means that the noise produced can be kept to a minimum.
- Lower cost. One challenge multi-GPU users face is the high budget stemming from the additional hardware required to run two graphics cards. A single GPU requires no additions as long as the existing PC hardware is capable of keeping up with it. For this reason, a single GPU is recommended for users on a budget.
Cons of Single-GPU Systems
One potential downside of a single-card setup is the potential for reduced reliability. The risk of an unanticipated component failure in a single-card system is always high. Without a replacement, it can be hard to recover from a sudden failure.
While both single-card and two-card setups can experience component failures, it can be more difficult to acquire a replacement with a single card.
Do You Need Two GPUs?
Whether or not you need two graphics cards depends on your needs and budget. Today, a pro gamer running two monitors simultaneously only needs one GPU for an enhanced gaming experience.
On the other hand, dedicated crypto miners would need a multi-GPU system to overcome the constraints of a single card.
If your PC doesn’t see much action in such applications, a single graphics card should suffice to cater to your needs. Any gamer, video editor, 3D artist, and the everyday user would benefit from a single high-end graphics card for a much lower cost.
While dual-GPU systems deliver worthwhile performances, their popularity fell to higher-end single-GPUs that can seamlessly achieve a similar result at a fraction of the cost.
Unless you desperately need two graphics cards for demanding applications or have an older GPU that could use a helping hand, I do not recommend investing in a dual-GPU setup.
It is expensive, and the benefits may fall short of your expectations.