Compare any two graphics cards:
GeForce GTX 660 vs Radeon HD 6990
IntroThe GeForce GTX 660 makes use of a 28 nm design. nVidia has clocked the core speed at 980 MHz. The GDDR5 memory is set to run at a frequency of 1502 MHz on this card. It features 960 SPUs along with 80 Texture Address Units and 24 ROPs.
Compare all that to the Radeon HD 6990, which features core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 Texture Address Units and 32 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6990 should theoretically be a lot faster than the GeForce GTX 660 overall. (explain)
Texel RateThe Radeon HD 6990 will be quite a bit (about 103%) better at anisotropic filtering than the GeForce GTX 660. (explain)
Pixel RateThe Radeon HD 6990 will be much (approximately 126%) more effective at FSAA than the GeForce GTX 660, and also will be able to handle 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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
Price ComparisonPlease note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.
Memory Bandwidth: Memory bandwidth is the largest amount of data (in units of megabytes per second) that can be transferred across the external memory interface within a second. It's calculated by multiplying the bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.