Radeon HD 4890 2GB vs Radeon R7 250X

Intro

Compare those specs to the Radeon R7 250X, which comes with a clock speed of 1000 MHz and a GDDR5 memory speed of 1125 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It features 640 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

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

Memory Bandwidth

In theory, the Radeon HD 4890 2GB is 73% quicker than the Radeon R7 250X overall, due to its higher bandwidth. (explain)

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

Texel Rate

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

Pixel Rate

Both cards have exactly the same pixel fill rate, so in theory they should be equally good at at FSAA, and be able to handle 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 max amount of information (in units of megabytes per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka 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 memory bandwidth is, the lower the ability to reach the maximum fill rate.