Compare any two graphics cards:
GeForce GTX 650 vs Radeon HD 4890 2GB
IntroThe GeForce GTX 650 comes with a core clock speed of 1058 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is made up of 384 SPUs, 32 Texture Address Units, and 16 ROPs.
Compare those specifications to the Radeon HD 4890 2GB, which has core clock speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 memory. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 4890 2GB should theoretically perform much faster than the GeForce GTX 650 overall. (explain)
Texel RateThe Radeon HD 4890 2GB will be just a bit (approximately 18%) more effective at AF than the GeForce GTX 650. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce GTX 650 is the winner, not by a very large margin though. (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 data (measured in MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.