Compare any two graphics cards:
GeForce 8600 GT 512MB DDR2 vs Radeon HD 5450
IntroThe GeForce 8600 GT 512MB DDR2 has core speeds of 540 MHz on the GPU, and 400 MHz on the 512 MB of DDR2 memory. It features 32 SPUs as well as 16 TAUs and 8 ROPs.
Compare those specs to the Radeon HD 5450, which features GPU clock speed of 650 MHz, and 512 MB of DDR3 memory set to run at 800 MHz through a 64-bit bus. It also features 80(16x5) SPUs, 8 TAUs, and 4 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so theoretically they should perform the same. (explain)
Texel RateThe GeForce 8600 GT 512MB DDR2 will be a lot (more or less 66%) better at AF than the Radeon HD 5450. (explain)
Pixel RateThe GeForce 8600 GT 512MB DDR2 is much (more or less 66%) better at anti-aliasing than the Radeon HD 5450, and also should be capable of handling higher resolutions without losing too much performance. (explain)
Memory Bandwidth: Bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's 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 are processed per second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the most pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.