In most cases, 2 GTX 1070 in SLI mode performs better than one GTX 1080. However, for the GTX 1080 Ti, the scenario is quite the opposite.
Comparison Between 2 GTX 1070 and 1 GTX 1080
2 GTX 1070 can be used as a combination of two GTX 1070 graphics cards in SLI mode, a high-performance technology that allows intelligently combination and scaling of graphics performance by having multiple NVIDIA GPUs in a single system. Its scaling geometry and fill rate performance technology boost performance for two combined GPUs.
The performance gain differs from game to game as it can range from no gains over a single GTX 1070 to up to 90% faster performance. However, for most games with SLI support, the GTX 1070 SLI is faster than a single GTX 1080. But the increased performance comes with a price, such as micro-stuttering due to rendering overlapping. Note that the power consumption is doubled (2x 150 = 300 Watts).
Have a look at this comparison chart between these two GPU lineups:
| GPU | NVIDIA GeForce GTX 1080 (Desktop) | NVIDIA GeForce GTX 1070 SLI (Desktop) |
| Codename | Pascal GP104 | Pascal GP104 SLI |
| Architecture | Pascal | Pascal |
| Pipelines | 2560 – unified | 3840 – unified |
| Core Speed | 1607 – 1733 (Boost) MHz | 1506 – 1683 (Boost) MHz |
| Memory Speed | 10000 MHz | 8000 MHz |
| Memory Bus Width | 256 Bit | 256 Bit |
| Memory Type | GDDR5X | GDDR5 |
| Max. Amount of Memory | 8 GB | 2x 8192 MB |
| Shared Memory | No | No |
| API | DirectX 12_1, OpenGL 4.5 | DirectX 12_1, OpenGL 4.5 |
| Power Consumption | 180 Watt | 300 Watt |
| Transistors | 7.2 Billion | 14.4 Billion |
| technology | 16 nm | 16 nm |
| Features | Multi-Projection, VR Ready, G-SYNC, Vulkan, Multi Monitor, 500-Watt system power recommended | Multi-Projection, VR Ready, G-SYNC, Vulkan, Multi-Monitor, CUDA, 3D Vision, PhysX, GeForce Experience, Surround, GameStream, GPU Boost 2.0, Adaptive Vertical Sync, SLI |
| Date of Announcement | 06.05.2016 = 2181 days old | 16.08.2016 = 2079 days old |
Benchmark Tests
Game benchmarks are one easy way to showcase a PC/GPU performance. You can have a clear overview of the performance with the FPS difference. Here are some popular game benchmarks tested with different resolutions. Note that the performance will differ on the peripherals used such as graphics memory, clock rate, RAM, processor, system settings, drivers, and operating system.
Fortnite (2018)
Low (1280×720)
GeForce GTX 1080 (Desktop): 327 FPS
GeForce GTX 1070 SLI (Desktop): 425.5 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 285 FPS
GeForce GTX 1070 SLI (Desktop): 279.5 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 199 FPS
GeForce GTX 1070 SLI (Desktop): 175.5 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 146 fps 84%
GeForce GTX 1070 SLI (Desktop): 123 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 45.7 FPS
GeForce GTX 1070 SLI (Desktop): 37.5 FPS
Middle-earth: Shadow of War (2017)
Low (1280×720)
GeForce GTX 1080 (Desktop): 170 FPS 130%
GeForce GTX 1070 SLI (Desktop): 111 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 154 FPS
GeForce GTX 1070 SLI (Desktop): 95 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 84 FPS
GeForce GTX 1070 SLI (Desktop): 81 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 102 FPS
GeForce GTX 1070 SLI (Desktop): 67 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 40 FPS
GeForce GTX 1070 SLI (Desktop): 45 FPS
FIFA 18 (2017)
Low (1280×720)
GeForce GTX 1080 (Desktop): 364 FPS
GeForce GTX 1070 SLI (Desktop): 344 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 351 FPS
GeForce GTX 1070 SLI (Desktop): 331 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 319 FPS
GeForce GTX 1070 SLI (Desktop): 310 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 315 FPS
GeForce GTX 1070 SLI (Desktop): 305 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 210 FPS
GeForce GTX 1070 SLI (Desktop): 187 FPS
Assassin´s Creed Origins (2017)
Low (1280×720)
GeForce GTX 1080 (Desktop): 101 FPS
GeForce GTX 1070 SLI (Desktop): 75 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 93 FPS
GeForce GTX 1070 SLI (Desktop): 72 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 91 FPS
GeForce GTX 1070 SLI (Desktop): 70 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 78 FPS
GeForce GTX 1070 SLI (Desktop): 61 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 40 FPS
GeForce GTX 1070 SLI (Desktop): 31 FPS
Destiny 2 (2017)
Low (1280×720)
GeForce GTX 1080 (Desktop): 168 FPS
GeForce GTX 1070 SLI (Desktop): 344 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 165 FPS
GeForce GTX 1070 SLI (Desktop): 119 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 160 FPS
GeForce GTX 1070 SLI (Desktop): 124 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 90 FPS
GeForce GTX 1070 SLI (Desktop): 120 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 40 FPS
GeForce GTX 1070 SLI (Desktop): 58 FPS
Ark Survival Evolved (2017)
Low (1280×720)
GeForce GTX 1080 (Desktop): 128 FPS
GeForce GTX 1070 SLI (Desktop): 121 FPS
Med. (1920×1080)
GeForce GTX 1080 (Desktop): 91 FPS
GeForce GTX 1070 SLI (Desktop): 85 FPS
High (1920×1080)
GeForce GTX 1080 (Desktop): 70 FPS
GeForce GTX 1070 SLI (Desktop): 81 FPS
Ultra (1920×1080)
GeForce GTX 1080 (Desktop): 48 FPS
GeForce GTX 1070 SLI (Desktop): 62 FPS
4K (3840×2160)
GeForce GTX 1080 (Desktop): 17 FPS
GeForce GTX 1070 SLI (Desktop): 26 FPS
2 GTX 1070 VS 1 1080 Ti
Now, let’s see some performance comparison between GeForce GTX 1080 Ti with 2 GeForce GTX 1070 with SLI mode.
Final Fantasy XV Benchmark (2018)
Low (1280×720)
GeForce GTX 1080 Ti (Desktop): 173 FPS
GeForce GTX 1070 SLI (Desktop): 132 FPS
Med. (1920×1080)
GeForce GTX 1080 Ti (Desktop): 131 FPS
GeForce GTX 1070 SLI (Desktop): 82 FPS
High (1920×1080)
GeForce GTX 1080 Ti (Desktop): 101 FPS
GeForce GTX 1070 SLI (Desktop): 57 FPS
4K (3840×2160)
GeForce GTX 1080 Ti (Desktop): 46 FPS
GeForce GTX 1070 SLI (Desktop): 24 FPS
Star Wars Battlefront 2Star Wars Battlefront 2 (2017)
Low (1280×720)
GeForce GTX 1080 Ti (Desktop): 179 FPS
GeForce GTX 1070 SLI (Desktop): 160 FPS
Med. (1920×1080)
GeForce GTX 1080 Ti (Desktop): 167 FPS
GeForce GTX 1070 SLI (Desktop): 145 FPS
High (1920×1080)
GeForce GTX 1080 Ti (Desktop): 142 FPS
GeForce GTX 1070 SLI (Desktop): 129 FPS
Ultra (1920×1080)
GeForce GTX 1080 Ti (Desktop): 155 FPS
GeForce GTX 1070 SLI (Desktop): 119 FPS
4K (3840×2160)
GeForce GTX 1080 Ti (Desktop): 56 FPS
GeForce GTX 1070 SLI (Desktop): 58 FPS
Fortnite (2018)
High (1920×1080)
GeForce GTX 1080 Ti (Desktop): 203 FPS
GeForce GTX 1070 SLI (Desktop): 175 FPS
Ultra (1920×1080)
GeForce GTX 1080 Ti (Desktop): 163 FPS
GeForce GTX 1070 SLI (Desktop): 123 FPS
4K (3840×2160)
GeForce GTX 1080 Ti (Desktop): 51 FPS
GeForce GTX 1070 SLI (Desktop): 37 FPS
To Conclude
As you can see, two GTX 1070 in SLI mode performs a lot better in most games compared to 1 GTX 1080. However, a single GTX 1080 Ti performs significantly better than two GTX 1070. Another thing to watch out that your two GTX 1070 in SLI mode draws double power from your PSU, which may cause overheating or bottleneck issue leading to permanent damage.
