Compare any two graphics cards:
GeForce GT 240 GDDR5 vs Radeon HD 4850 X2 1GB
IntroThe GeForce GT 240 GDDR5 has a GPU clock speed of 550 MHz, and the 512 MB of GDDR5 RAM runs at 850 MHz through a 128-bit bus. It also features 96 SPUs, 32 TAUs, and 8 ROPs.
Compare that to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has clocked the core speed at 625 MHz. The GDDR3 memory works at a frequency of 993 MHz on this specific model. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 4850 X2 1GB should perform quite a bit faster than the GeForce GT 240 GDDR5 in general. (explain)
Texel RateThe Radeon HD 4850 X2 1GB is much (more or less 184%) faster with regards to texture filtering than the GeForce GT 240 GDDR5. (explain)
Pixel RateThe Radeon HD 4850 X2 1GB is much (about 355%) more effective at full screen anti-aliasing than the GeForce GT 240 GDDR5, and also will be capable of handling higher resolutions while still performing well. (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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 max amount of information (in units of megabytes per second) that can be transported across 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 type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.