Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 7990
IntroThe GeForce GT 640 DDR3 uses a 28 nm design. nVidia has set the core frequency at 900 MHz. The DDR3 RAM runs at a frequency of 1782 MHz on this card. It features 384 SPUs as well as 32 TAUs and 16 Rasterization Operator Units.
Compare those specifications to the Radeon HD 7990, which has clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 Texture Address Units and 32 ROPs.
BenchmarksThese are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.
3DMark Fire Strike Graphics Score
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 7990 should theoretically be much better than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe Radeon HD 7990 is a lot (about 744%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 7990 will be a lot (approximately 322%) more effective at FSAA than the GeForce GT 640 DDR3, and also capable of handling higher resolutions without slowing down too much. (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 GT 640 DDR3
Radeon HD 7990
Memory Bandwidth: Bandwidth is the largest amount of information (in units of MB per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.
GeForce GT 640 DDR3
Radeon HD 7990