Before getting started, here's a list of relevant Pascal & GTX 1080 articles we wrote:

• NVidia Pascal GP100 Architecture Overview

• GTX 1080 Founders Edition Review & In-Depth Benchmark (9000 words!)

• Building Our Own GTX 1080 Hybrid – Tearing Apart the Founders Edition

• Building Our Own GTX 1080 Hybrid – Performance Results

• What We Learned from Our GTX 1080 Hybrid Experiment

Our review of the GTX 1070 Founders Edition graphics card will compare it vs. the GTX 1080, 980 Ti, 970 (and more) and AMD's R9 Fury X & R9 390X. We'll look at performance (FPS) benchmarks and our specialized thermal testing with endurance (clock-rate vs. time) burn-in. These tests explore major points of issue for new GPUs, and provide a closer look at real-world gaming performance. We're in Taipei, Taiwan right now for Computex, and so we've culled a few tests due to travel complications. Power draw did not make it into this review.

NVIDIA GeForce GTX 1070 vs. GTX 1080, 980 Ti, 970, & 390X [Video]

NVIDIA GeForce GTX 1070 Specs vs. 1080, 970, 980 Ti

Architecture Revisit – GP104-200 Simultaneous Multiprocessors, GPCs, TPCs

The GTX 1070 utilizes the same Pascal GP104 architecture as found on the GTX 1080, though the *-200 subversion (rather than *-400) does bring some changes. Those changes are mostly to core count and clock speed.

The silicon is the same, the architecture is mostly the same, but the die has been somewhat simplified on the GTX 1070 to reduce cost. The heart of the chip is still 16nm FinFET design, which operates at slightly lower voltage than planar process and exhibits less power leakage than planar. Datapath optimizations are also in-place for performance improvements, something we spent a few thousand words on in our 1080 review.

(Above: The GP104-400 block diagram. Remove one GPC -- that's basically GP104-200.)

(Above: SM architecture on Pascal / GP104.)

NVidia's GTX 1070 runs 15 SMs rather than the 20 SMs of GP104-400, reducing core count to 1920 and TMUs to 120 (capable of 202GT/s). The clock boosts to 1683MHz, but has OC headroom that we play with later in this review.

Another major change from the 1080 is the GTX 1070's usage of GDDR5 8Gbps memory, rather than the new GDDR5X 10Gbps memory of the GTX 1080. This reduces cost of the card by mounting a more ubiquitous memory platform to the device.

To learn about asynchronous compute and memory subsystems on Pascal, check out our 9000-word review on the GTX 1080.

Game Test Methodology

We tested using our GPU test bench, detailed in the table below. Our thanks to supporting hardware vendors for supplying some of the test components.

The latest AMD drivers (16.15.2.1 Doom-ready) were used for testing. NVidia's unreleased press drivers were used for game (FPS) testing. Game settings were manually controlled for the DUT. All games were run at presets defined in their respective charts. We disable brand-supported technologies in games, like The Witcher 3's HairWorks and HBAO. All other game settings are defined in respective game benchmarks, which we publish separately from GPU reviews. Our test courses, in the event manual testing is executed, are also uploaded within that content. This allows others to replicate our results by studying our bench courses.

Windows 10-64 build 10586 was used for testing.

Each game was tested for 30 seconds in an identical scenario, then repeated three times for parity. Some games have multiple settings or APIs under test, leaving our test matrix to look something like this:

Average FPS, 1% low, and 0.1% low times are measured. We do not measure maximum or minimum FPS results as we consider these numbers to be pure outliers. Instead, we take an average of the lowest 1% of results (1% low) to show real-world, noticeable dips; we then take an average of the lowest 0.1% of results for severe spikes.

For Dx12 and Vulkan API testing, we use built-in benchmark tools and rely upon log generation for our metrics. That data is reported at the engine level.

Video Cards Tested

• NVIDIA GTX 1080 Founders Edition ($700)
• NVIDIA GTX 980 Ti Reference ($650)
• NVIDIA GTX 980 Reference ($460)
• NVIDIA GTX 980 2x SLI Reference ($920)
• AMD R9 Fury X 4GB HBM ($630)
• AMD MSI R9 390X 8GB ($460)

Thermal Test Methodology

We strongly believe that our thermal testing methodology is the best on this side of the tech-media industry. We've validated our testing methodology with thermal chambers and have proven near-perfect accuracy of results.

Conducting thermal tests requires careful measurement of temperatures in the surrounding environment. We control for ambient by constantly measuring temperatures with K-Type thermocouples and infrared readers. We then produce charts using a Delta T(emperature) over Ambient value. This value subtracts the thermo-logged ambient value from the measured diode temperatures, producing a delta report of thermals. AIDA64 is used for logging thermals of silicon components, including the GPU diode. We additionally log core utilization and frequencies to ensure all components are firing as expected. Voltage levels are measured in addition to fan speeds, frequencies, and thermals. GPU-Z is deployed for redundancy and validation against AIDA64.

All open bench fans are configured to their maximum speed and connected straight to the PSU. This ensures minimal variance when testing, as automatically controlled fan speeds will reduce reliability of benchmarking. The CPU fan is set to use a custom fan curve that was devised in-house after a series of testing. We use a custom-built open air bench that mounts the CPU radiator out of the way of the airflow channels influencing the GPU, so the CPU heat is dumped where it will have no measurable impact on GPU temperatures.

We use an AMPROBE multi-diode thermocouple reader to log ambient actively. This ambient measurement is used to monitor fluctuations and is subtracted from absolute GPU diode readings to produce a delta value. For these tests, we configured the thermocouple reader's logging interval to 1s, matching the logging interval of GPU-Z and AIDA64. Data is calculated using a custom, in-house spreadsheet and software solution.

Endurance tests are conducted for new architectures or devices of particular interest, like the GTX 1080, R9 Fury X, or GTX 980 Ti Hybrid from EVGA. These endurance tests report temperature versus frequency (sometimes versus FPS), providing a look at how cards interact in real-world gaming scenarios over extended periods of time. Because benchmarks do not inherently burn-in a card for a reasonable play period, we use this test method as a net to isolate and discover issues of thermal throttling or frequency tolerance to temperature.

Our test starts with a two-minute idle period to gauge non-gaming performance. A script automatically triggers the beginning of a GPU-intensive benchmark running MSI Kombustor – Titan Lakes for 1080s. Because we use an in-house script, we are able to perfectly execute and align our tests between passes.