Compare any two graphics cards:
GeForce GTX 580 vs Radeon HD 7970
IntroThe GeForce GTX 580 comes with a GPU core clock speed of 772 MHz, and the 1536 MB of GDDR5 RAM runs at 1002 MHz through a 384-bit bus. It also is comprised of 512 SPUs, 64 TAUs, and 48 ROPs.
Compare those specifications to the Radeon HD 7970, which comes with core clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 TAUs and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 7970 should be a lot faster than the GeForce GTX 580 in general. (explain)
Texel RateThe Radeon HD 7970 will be quite a bit (approximately 140%) faster with regards to anisotropic filtering than the GeForce GTX 580. (explain)
Pixel RateThe GeForce GTX 580 will be a lot (about 25%) faster with regards to full screen anti-aliasing than the Radeon HD 7970, and will be capable of handling higher resolutions while still performing well. (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.
Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
Memory Bandwidth: Memory bandwidth is the largest amount of data (measured in megabytes per second) that can be transported across the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This 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 video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.