Compare any two graphics cards:
GeForce GTX 260 vs Radeon HD 4890 1GB
IntroThe GeForce GTX 260 comes with a GPU core speed of 576 MHz, and the 896 MB of GDDR3 RAM is set to run at 999 MHz through a 448-bit bus. It also is comprised of 192 Stream Processors, 64 TAUs, and 28 Raster Operation Units.
Compare those specs to the Radeon HD 4890 1GB, which features a clock frequency of 1000 MHz and a GDDR5 memory frequency of 975 MHz. It also features a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 4890 1GB, in theory, should perform just a bit faster than the GeForce GTX 260 overall. (explain)
Texel RateThe Radeon HD 4890 1GB is a bit (more or less 9%) better at AF than the GeForce GTX 260. (explain)
Pixel RateThe GeForce GTX 260 should be a small bit (more or less 1%) faster with regards to anti-aliasing than the Radeon HD 4890 1GB, and should be able to handle higher screen 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.
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 maximum amount of data (measured in MB per second) that can be transported over the external memory interface in a second. It is calculated by multiplying the interface width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.