Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 6670 (OEM) 1GB
IntroThe GeForce GT 640 DDR3 features a GPU core speed of 900 MHz, and the 2048 MB of DDR3 RAM runs at 1782 MHz through a 128-bit bus. It also is made up of 384 Stream Processors, 32 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon HD 6670 (OEM) 1GB, which comes with clock speeds of 800 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 480 SPUs along with 24 Texture Address Units and 8 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6670 (OEM) 1GB is 12% quicker than the GeForce GT 640 DDR3 overall, because of its greater data rate. (explain)
Texel RateThe GeForce GT 640 DDR3 is much (approximately 50%) faster with regards to anisotropic filtering than the Radeon HD 6670 (OEM) 1GB. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is a better choice, and very much so. (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 information (measured in MB per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better 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 can be applied per second. This is calculated by multiplying the total 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 one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour 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 output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.