Compare any two graphics cards:
GeForce 8800 GTS (G80) 640MB vs Radeon HD 4650 1GB
IntroThe GeForce 8800 GTS (G80) 640MB comes with core clock speeds of 513 MHz on the GPU, and 792 MHz on the 640 MB of GDDR3 memory. It features 96 SPUs as well as 48 Texture Address Units and 20 Rasterization Operator Units.
Compare all of that to the Radeon HD 4650 1GB, which features clock speeds of 600 MHz on the GPU, and 700 MHz on the 1024 MB of GDDR3 memory. It features 320(64x5) SPUs as well as 32 TAUs and 8 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce 8800 GTS (G80) 640MB should be quite a bit faster than the Radeon HD 4650 1GB overall. (explain)
Texel RateThe GeForce 8800 GTS (G80) 640MB will be quite a bit (approximately 28%) more effective at texture filtering than the Radeon HD 4650 1GB. (explain)
Pixel RateIf using a high screen resolution is important to you, then the GeForce 8800 GTS (G80) 640MB 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: Bandwidth is the maximum amount of information (measured in MB per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 number of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, 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 number of pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.