Compare any two graphics cards:
GeForce 840M vs Radeon HD 5450
IntroThe GeForce 840M uses a 28 nm design. nVidia has set the core speed at 1029 MHz. The DDR3 RAM runs at a frequency of 1000 MHz on this card. It features 384 SPUs as well as 24 Texture Address Units and 8 Rasterization Operator Units.
Compare all that to the Radeon HD 5450, which comes with a clock frequency of 650 MHz and a DDR3 memory frequency of 800 MHz. It also makes use of a 64-bit bus, and uses a 40 nm design. It features 80(16x5) SPUs, 8 TAUs, and 4 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce 840M will be 25% quicker than the Radeon HD 5450 in general, because of its greater bandwidth. (explain)
Texel RateThe GeForce 840M will be much (more or less 375%) faster with regards to AF than the Radeon HD 5450. (explain)
Pixel RateThe GeForce 840M is a lot (more or less 217%) better at full screen anti-aliasing than the Radeon HD 5450, and able to handle higher screen resolutions without losing too much performance. (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: Bandwidth is the max amount of data (in units of megabytes per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. 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 amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total number 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. 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 memory bandwidth is, the lower the ability to get to the maximum fill rate.