Radeon HD 7770 vs Radeon R7 250X 2GB

Intro

Compare those specifications to the Radeon R7 250X 2GB, which makes use of a 28 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 RAM is set to run at a speed of 1125 MHz on this card. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

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 the exact same memory bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

Both cards have the exact same texel fill rate, so theoretically 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 FSAA, 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: Memory bandwidth is the largest amount of information (measured in megabytes per second) that can be transported past the external memory interface within a second. The number is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 number of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.