▷ What is sli and what is it for

SLI is the name of a Nvidia technology that has been with us for many years, in fact it has been around for so long that geeks take it for granted that everyone knows what it means and what it stands for. Everyone knows what SLI is and how it works, except for people who have not been following the hardware for the past ten years. For this reason we have prepared a special post to explain what SLI technology is.

Index of contents

What is SLI technology

SLI technically stands for Scalable Link Interface. It is the term used by the graphics card company Nvidia to describe the way it connects multiple GPUs. Technology is a form of parallel processing that enables up to four Nvidia GPUs to work together to render a game at extremely high frame rates.

We recommend reading our post about Nvidia GTX 1080 Review in Spanish

However, as often happens, the term SLI is often used generically to describe all similar technologies. Competitor AMD uses the name CrossFire to describe their own version of this concept, but enthusiasts sometimes call it SLI by mistake or because they don't feel like writing the full word "CrossFire."

There is also a company called Hydra that makes a chip that allows multiple GPUs, even those of different brands, to work as one. This is also sometimes generically called a form of SLI. Whatever the situation or brand, if anyone mentions SLI, they are talking about using multiple GPUs to render a game.

When SLI was first introduced, the technology was used only to connect multiple video cards. In 2005, however, Gigabyte introduced a video card that used SLI technology to connect two different Nvidia GPUs located on the same video card. This arrangement has become more common over time. Both Nvidia and AMD have released reference design cards with two GPUs on the same video card connected via SLI or CrossFire.

This has somewhat confused things because two video cards with two GPUs each would technically be a quad layout, although only two video cards are involved. That said, these cards are expensive and therefore rare, so it can generally be assumed that if someone is talking about SLI they are talking about using two or more video cards.

Nvidia has also paired a discrete GPU with an integrated GPU in the past. This was marked with the term Hybrid SLI. However, Nvidia was forced to abandon the chipset business soon after, which meant that the company no longer offered integrated graphics. Hybrid SLI is effectively dead as a result.

When SLI originally debuted, it was intended to connect two video cards with the same GPU. The cards could be from different manufacturers, but they had to be from the same Nvidia series. This is generally still the case. There are exceptions, but they are few and generally not worth it.

What benefits can SLI bring me?

Many people unfamiliar with this technology assume that two cards will be twice as fast as one, this assumption is incorrect. There is an overhead associated with obtaining two or more GPUs to work together, and driver and game support for the feature are also determining factors. At best, an SLI setup will be 80% faster than a single card. In the worst case, it can actually be slower.

All versions of this technology have come a long way over the years, but there can still be problems. A common problem is micro-stuttering. This is a stuttering perception that players sometimes experience with SLI settings but that does not appear in the game's frame rate per second.

WE RECOMMEND YOU GeForce 398.86 solves the problem with G-SYNC and Windows April 2018 Update

SLI Performance Testing Is it worth it or not?

To analyze the performance of SLI configurations, we have relied on tests of the Benchmark medium. In this case the GeForce GTX 1080 Ti has been used, both in configuration of two cards and one. Testing has been done in 4K resolution to remove any bottlenecks from the processor. The following table shows the results obtained:

Try 4K games
	GeForce GTX 1080 Ti	GeForce GTX 1080 Ti SLI
Far Cry 5	55	60
PUBG	59	66
GTA V	73	97
The Witcher 3	58	66
Hitman	76	74
Rise of the Tomb Raider	57	106
Battlefield 1	73	67
Resident Evil 7	66	62
For Honor	58	97
The Division	55	47

Final words and conclusion

As we have seen, the technology is far from achieving a great increase in the performance of games compared to using a single graphics card, to this we must add the problems of micro-stuttering in the image that are not reflected in a benchmark. Only in the cases of Rise of The Tomb Raider, For Honor and GTA V is there a clear increase in performance.

If you liked this article, you will surely be interested in reading one of our guides:

• Best processors on the market Best motherboards on the market Best RAM memory on the market Best graphics cards on the market Best SSDs on the market

To this we must add other drawbacks, such as the fact that two cards consume twice as much energy as one and generate twice as much heat, increasing the electricity bill and generating the need for better ventilation of the PC. That is why manufacturers are increasingly leaving aside SLI and CrossFire technology, as it brings many more problems than benefits. We can only wait as the new Nvidia NVLink technology evolves and if there really is the improvement that Nvidia promises.

This ends our post on SLI technology, remember that you can leave a comment if you have something to add.