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

Intro

Compare those specs to the Radeon R7 250X 2GB, which features a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also is comprised of 640 Stream Processors, 40 TAUs, and 16 ROPs.

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

In theory, the Radeon HD 4890 2GB should be 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 theoretically they should perform equally good at at full screen anti-aliasing, 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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the bus 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 higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines 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 lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.