Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 7750
IntroThe GeForce GT 640 DDR3 features a GPU core clock speed of 900 MHz, and the 2048 MB of DDR3 RAM is set to run at 1782 MHz through a 128-bit bus. It also features 384 Stream Processors, 32 TAUs, and 16 ROPs.
Compare those specifications to the Radeon HD 7750, which has GPU core speed of 800 MHz, and 1024 MB of GDDR5 RAM set to run at 1125 MHz through a 128-bit bus. It also is made up of 512 SPUs, 32 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7750 is 26% faster than the GeForce GT 640 DDR3 overall, due to its greater data rate. (explain)
Texel RateThe GeForce GT 640 DDR3 should be just a bit (about 13%) more effective at anisotropic filtering than the Radeon HD 7750. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is a better choice, though not 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.
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 maximum amount of data (in units of megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.