Radeon HD 7770 vs Radeon R7 250X 2GB

Intro

Compare that to the Radeon R7 250X 2GB, which comes with GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also features 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon R7 250X 2GB		95 Watts
	Difference: 15 Watts (19%)

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

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

Pixel Rate

Both cards have the exact same pixel fill rate, so in theory they should perform equally good at at anti-aliasing, and be able to handle the same screen 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 largest amount of data (measured in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, 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 graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.