Performance: Real-World Results
When shopping for a graphics card, one of the chief features you should evaluate is real-world performance, and modern games are designed to push graphics hardware to its limits. One of the best measures of in-game performance is the frames per second (fps) a graphics card can produce while running the game. We evaluated the products in this lineup against several popular, graphics-intensive games to see how they handled the load.
As you might expect, the best video cards in our lineup consistently exceeded 60 fps in these tests. Some cards reached speeds of almost 180 fps. Even our fourth-place card, the Nvidia GeForce GTX 780, produced 60 fps results across the board. Most of the less powerful cards struggled to keep up with one or more of the games we used for these graphics card tests, regularly dipping into the 45-55 fps range. The two lowest-ranked cards in our lineup, the Nvidia GeForce GTX 760 and the Nvidia GeForce GTX 670, bottomed out at about 40 fps while running "Thief."
Using games for performance testing has a subjective element, player action, so we also evaluated these products using two benchmark applications. These programs perform a consistent series of graphics-rendering tasks, providing a more objective measurement of performance. The Unigine Heaven benchmark measures its results in fps, and the lineup results ranged from 45.4 to 99.2 fps. The top-ranked Nvidia GeForce GTX 980 left its nearest competitors, the GTX 970 and the AMD Radeon R9 290X, in the dust, surpassing their scores by over 20 fps. It also nearly doubled the scores of our three lowest-ranked cards, illustrating the speed at which graphics hardware improves.
Our next test, the 3DMark Fire Strike benchmark, generates a generic score value, which ranged from a low of 6,971 to a high of 13,297. Once again, the top-ranked card pulled a very high score compared to the rest of the lineup. The two benchmarks produce very different raw values, but the proportional differences between individual graphics card scores are similar.
In our final graphics card test, we evaluated each product at 2160p, also known as 4K UHD resolution or simply 4K, to see how well they handled the stress of very high-quality displays. All cards struggled with this test. The Nvidia GeForce GTX 980 managed 58.3 fps, which is acceptable performance for many gamers, but other scores dropped off sharply. The AMD Radeon R9 290X had the second-highest score in this test: 51.3 fps. The lowest-rated cards in our lineup, the GTX 760 and the GTX 670, failed to reach 30 fps. If you're interested in using a 2160p display, you may want to take advantage of SLI or Crossfire and use multiple graphics cards in your computer.
GPUs and Memory: The Graphics Workhorses
Both Nvidia and AMD design and produce their own GPUs and supporting hardware, and both manufacturers' GPUs use multiple processor cores to handle graphics manipulation tasks. The exact features and capabilities of these cores differ, but, in general, more cores with faster clock speeds means more graphics processing power. We compared core counts and clock speeds as general indicators of processing power when we created our graphics card rankings.
Graphics processing cores use lots of data. The fastest processor is useless if it has nothing to work with. When evaluating graphics cards, you need to consider both the card's memory capacity, or how much data it can store, and its memory bandwidth, the speed at which it can deliver stored data to the cores. In general, more powerful cards have more memory. The majority of cards in this lineup have 2GB to 3GB of RAM, while the top two cards have 4GB. The AMD Radeon R9 290X, our third-place card, raises the stakes here with 8GB of RAM.
Measuring data access speed, memory bandwidth, is a bit tricky. You need to consider both bus width and memory clock speed. Memory bus width is a measure of how many bits of data can be sent to the GPU at once, while the memory clock controls how fast the bits move. If you think of data as dirt, the memory clock measures how fast you dig, and the memory bus width is the size of the shovel you use. You can use memory clock speed and memory bus width to calculate overall memory bandwidth, or the speed at which information moves from memory storage to the GPU.
The best graphics cards have high bandwidth so they can transfer the data needed to render constantly changing in-game scenes to the GPU quickly and efficiently. Once again, the AMD Radeon R9 290X tops the charts; its relatively slow 5MHz memory clock controls a 512-bit bus, providing 320 GBps memory bandwidth. Surprisingly, two midrange cards, the Nvidia GeForce GTX 770 and GTX 680, have more memory bandwidth, about 288 GBps, than our two top picks, which cap out at 224 GBps.
Processor cores and memory bandwidth all work toward a single purpose: getting processed image data to your display. We've used texture fillrate and pixel fillrate to measure this capability. Most graphics applications, including most games, model the images they display using geometric meshes. The faces of these meshes are filled with image data called textures, and each texture is composed of many texels, a fundamental graphics element. The texture fillrate is a measure of how fast the GPU can process texels. It's measured in gigatexels per second (GTps).
Pixels are a measure of display screen real estate. When you're talking about resolutions like 1920 x 1080, you're talking about pixels. Pixel fillrate measures how fast the processor can send pixel data to your display. Pixel fillrates are measured in gigapixels per second (GPps). High texture fillrates are critical for rendering complex scenes efficiently, while high pixel fillrates are required to support high-resolution screens or multiple displays. As you might expect, the best graphics cards have faster texture and pixel fillrates. The AMD Radeon R9 290X uses its memory bandwidth to achieve the best texture fillrate, 176 GTps, while the GTX 780 clocks in at a close second, 166 GTps. Our top choice, the Nvidia GeForce GTX 980, achieves a somewhat disappointing 144 GTps texture fillrate, but it gets top marks for pixel fillrate, managing an impressive 72.1 GPps.