Compare any two graphics cards:
Geforce GTX 690 vs Radeon HD 7990
IntroThe Geforce GTX 690 has clock speeds of 915 MHz on the GPU, and 1502 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs along with 128 TAUs and 32 Rasterization Operator Units.
Compare those specs to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core speed at 950 MHz. The GDDR5 RAM works at a speed of 1500 MHz on this particular model. It features 2048 SPUs along with 128 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 7990 should be quite a bit faster than the Geforce GTX 690 overall. (explain)
Texel RateThe Radeon HD 7990 will be a bit (about 4%) better at texture filtering than the Geforce GTX 690. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 7990 is the winner, but it probably won't make a huge difference. (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.
Geforce GTX 690
Radeon HD 7990
Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of MB per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 amount of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total amount of texture units by the core clock 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 processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.
Geforce GTX 690
Radeon HD 7990