Radeon HD 4890 1GB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which comes with clock speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 RAM. 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 HD 4890 1GB		190 Watts
	Difference: 110 Watts (138%)

Memory Bandwidth

In theory, the Radeon HD 4890 1GB should be quite a bit faster than the Radeon HD 7770 overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 52800 (73%)

Texel Rate

Both cards have the exact same texel 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 theoretically they should perform equally good at at full screen anti-aliasing, and be capable of handling 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 max amount of data (measured in megabytes per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs 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 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.