Radeon HD 4890 2GB vs Radeon R7 250X 2GB

Intro

Compare that to the Radeon R7 250X 2GB, which makes use of a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 memory works at a speed of 1125 MHz on this model. It features 640 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R7 250X 2GB		95 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 95 Watts (100%)

Memory Bandwidth

Theoretically, the Radeon HD 4890 2GB should perform much faster than the Radeon R7 250X 2GB overall. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon R7 250X 2GB		72000 MB/sec
	Difference: 52800 (73%)

Texel Rate

Both cards have the exact same texel fill rate, so theoretically they should perform equally good at at AF. (explain)

Pixel Rate

Both cards have the exact same pixel fill rate, so in theory they should perform equally good at at full screen anti-aliasing, and be capable of handling the same resolutions. (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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of MB per second) that can be moved across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 again. If 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 high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units by the core 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 per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.