Compare any two graphics cards:
GeForce GTS 450 vs Radeon HD 4850 1GB
IntroThe GeForce GTS 450 has a GPU clock speed of 783 MHz, and the 512 MB of GDDR5 memory runs at 902 MHz through a 128-bit bus. It also is made up of 192 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 4850 1GB, which comes with a core clock speed of 625 MHz and a GDDR4 memory frequency of 993 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 4850 1GB is 10% quicker than the GeForce GTS 450 overall, because of its higher data rate. (explain)
Texel RateThe GeForce GTS 450 will be a bit (more or less 0%) better at anisotropic filtering than the Radeon HD 4850 1GB. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GTS 450 is superior to the Radeon HD 4850 1GB, 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: Bandwidth is the largest amount of data (measured in MB per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses 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 high 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 texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs 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 also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.