Compare any two graphics cards:
Geforce GTX 680 vs Radeon R9 M390X
IntroThe Geforce GTX 680 uses a 28 nm design. nVidia has clocked the core frequency at 1006 MHz. The GDDR5 RAM works at a frequency of 1502 MHz on this particular card. It features 1536 SPUs along with 128 TAUs and 32 Rasterization Operator Units.
Compare those specifications to the Radeon R9 M390X, which features core speeds of 723 MHz on the GPU, and 1250 MHz on the 4096 MB of GDDR5 RAM. It features 2048 SPUs along with 128 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Geforce GTX 680 should in theory be a little bit faster than the Radeon R9 M390X overall. (explain)
Texel RateThe Geforce GTX 680 should be much (approximately 39%) faster with regards to AF than the Radeon R9 M390X. (explain)
Pixel RateIf using a high resolution is important to you, then the Geforce GTX 680 is superior to the Radeon R9 M390X, by far. (explain)
Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.
Memory Bandwidth: Memory bandwidth is the max amount of information (counted in MB per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.