Technology g

Some users have reported that the use of G-Sync technology is a performance penalty associated with its use in SLI configurations. The problem is simple: According to the posts on the Nvidia forums and on the Nvidia subreddit, activating G-Sync at the same time as SLI causes significant drops in the performance of many games.

G-Sync penalizes performance in SLI configurations

SLI is Nvidia's technology to use more than one GPU to render a scene at the same time, while G-Sync is a technology that smoothes frame rates compared to standard V-Sync, ensuring that the monitor is synchronized with the GPU refresh rate.

We recommend reading our post on What is rasterization and what is its difference with Ray Tracing

Both G-Sync and SLI have important time implications. Keeping the GPU and monitor in sync takes time. Moving data from one GPU to another and then displaying frames rendered by that same GPU takes time. If you are aiming at a frame rate of 30 fps, the system must deliver a new frame every 33.3 ms. If you want to run a game at 60 fps, that means you need a new frame every 16.6 ms. This time required for each frame, is reduced as you increase the frame rate per second, and at a certain moment, you have a very limited window with which to work.

The Extremetech team decided to test the situation with a pair of GTX 1080 GPUs, the highest level cards they have, along with a Core i7 8086K processor to avoid bottlenecks. The monitor used was an Acer XB280HK. The results are clear, under 4K resolution, turning on G-Sync technology in a two GeForce GTX 1080 SLI configuration causes the system to lose performance.

At the moment the exact cause of this decrease in performance is not known, although it is clear that it exists, despite the fact that Nvidia has always claimed that the G-Sync does not lose performance. Nvidia should work to try to fix this problem.

Extremetech font