The 50-game GTX 1070 Ti SLI Review


The 50-game Mega GTX 1070 Ti SLI Review

Enthusiasts are looking forward to NVIDIA’s next generation of GPUs as a cryptocurrency mining boom is driving the prices of video cards way up.  However, whenever there is a boom it is usually followed by a bust, and perhaps inexpensive used and even new Pascal video cards may become available in large quantities before too long. 

Some gamers may be tempted to wait for the next generation’s highest-end video cards by buying a second GTX 1070/1070 Ti/1080/1080 Ti for SLI as an interim solution, and skipping the second-tier next-generation cards that may be offered first.  How well does Pascal SLI scale and is it worth buying a second video card for SLI if and when they become reasonably priced?

BTR is very interested in multi-GPU scaling because adding a second video card in SLI offers a good way to nearly double a video card’s performance!  Our last SLI benching evaluation used Core i7-8700K at 4.6 GHz to test 35 games.  When GTX 1070 Ti SLI scaled well, it was significantly faster than a single GTX 1080 Ti, but it did not always scale.  We have tested SLI and CrossFire many times with rather mixed results, and this time we will bring you 51 games.

After finding that nearly half of our then 25-game benchmark suite had scaling issues with SLI just eleven months ago, we concluded that if you play the very latest games on Day 1 and rarely revisit your games, SLI may not be your best choice.  Just 2-1/2 months ago, we purchased a second GTX 1070 Ti and we ran 35 game benchmarks with better results for SLI on a new platform: Coffee Lake Core i7-8700K with all six cores overclocked to 4.6 GHz, and 16 GB HyperX DDR4 at 3333 MHz.  Now we are benching at 4.7 GHz and have added 16 games for a total of 51.

Our EVGA Z370 FTW motherboard allows for a full space between the SLI’d cards, and temperatures are never an issue although the GTX 1070 Ti Founders Edition runs hotter as the top card because it is heated from below by the Gigabyte GTX 1070 Ti, and its average locked-on Boost in SLI is 1911 MHz while the Gigabyte card manages 1923 MHz.

The High Bandwidth SLI Bridge

Flexible ribbon SLI bridges that have been generally bundled free with SLI motherboards don’t carry enough bandwidth for upper-midrange Pascal SLI which is why some motherboard manufacturers are now including generic-looking High Bandwidth (HB) SLI bridges. 

SLI ribbon bridge (Left), ASUS HB bridge (center), and ASRock HB bridge (Right) included with the motherboard.

HB bridges are necessary to support sufficient bandwidth for high-resolution  displays.  Below is a chart from the NVIDIA GTX 1080 Reviewer’s Guide that can also be applied to the GTX 1070 Ti as they are relatively close in performance:

We didn’t see see any FPS performance differences between using a single ribbon SLI bridge versus using the HB SLI bridge for GTX 1070 Ti SLI.  Rather we noticed an improvement in frametime delivery – smoothness is improved by using the higher bandwidth provided by the HB bridge over a ribbon SLI bridge. 

Is it OK to use 2 Standard Flexible Ribbon Bridges?

We found no positive performance improvement by using two ribbon SLI bridges over one bridge contrary to popular opinion.  NVIDIA confirmed to BTR that using 2 ribbon bridges together are not recommended:

“With the ribbon cable system, each SLI connection runs independently regardless, so adding the second ribbon provides no benefit.”

Let’s check out the test configuration.