Compare any two graphics cards:
GeForce GTX 660 vs Radeon HD 7770
IntroThe GeForce GTX 660 features a GPU core speed of 980 MHz, and the 2048 MB of GDDR5 RAM runs at 1502 MHz through a 192-bit bus. It also is made up of 960 Stream Processors, 80 Texture Address Units, and 24 ROPs.
Compare all that to the Radeon HD 7770, which features a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also is comprised of 640 Stream Processors, 40 Texture Address Units, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 660 should be 100% quicker than the Radeon HD 7770 overall, because of its greater data rate. (explain)
Texel RateThe GeForce GTX 660 will be much (more or less 96%) faster with regards to AF than the Radeon HD 7770. (explain)
Pixel RateIf running with a high resolution is important to you, then the GeForce GTX 660 is a better choice, by a large margin. (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 max amount of data (in units of MB per second) that can be moved over the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling 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 that the graphics chip can 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 core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.