Radeon HD 4890 1GB vs Radeon HD 7970

Intro

Compare those specs to the Radeon HD 7970, which features clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 7970		250 Watts
	Difference: 60 Watts (32%)

Memory Bandwidth

In theory, the Radeon HD 7970 is 112% faster than the Radeon HD 4890 1GB overall, due to its higher data rate. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 139200 (112%)

Texel Rate

The Radeon HD 7970 is much (approximately 196%) more effective at texture filtering than the Radeon HD 4890 1GB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 78400 (196%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7970 is the winner, by far. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 13600 (85%)

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 data (in units of MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of 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 better 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 are processed in one second. This is calculated by multiplying the total number of texture units 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 applied in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated 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 filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.