Compare any two graphics cards:
Geforce GTX 770 vs Radeon HD 7990
IntroThe Geforce GTX 770 features clock speeds of 1046 MHz on the GPU, and 1753 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs as well as 128 Texture Address Units and 32 ROPs.
Compare those specs to the Radeon HD 7990, which comes with a clock speed of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also uses a 384-bit memory bus, and uses a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 7990 should in theory be much better than the Geforce GTX 770 in general. (explain)
Texel RateThe Radeon HD 7990 is quite a bit (approximately 82%) faster with regards to AF than the Geforce GTX 770. (explain)
Pixel RateThe Radeon HD 7990 is a lot (more or less 82%) faster with regards to full screen anti-aliasing than the Geforce GTX 770, and should be capable of handling higher resolutions more effectively. (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: Bandwidth is the maximum amount of data (measured in megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in a 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 - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant 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.