Radeon HD 4870 1GB vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has clocked the core speed at 800 MHz. The GDDR5 RAM works at a speed of 1250 MHz on this specific model. It features 1792 SPUs as well as 112 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 4870 1GB		150 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 50 Watts (33%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 3GB will be 108% quicker than the Radeon HD 4870 1GB in general, because of its higher bandwidth. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon HD 7950 3GB should be much (approximately 199%) more effective at anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 59600 (199%)

Pixel Rate

The Radeon HD 7950 3GB should be quite a bit (more or less 113%) more effective at AA than the Radeon HD 4870 1GB, and will be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 13600 (113%)

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 (counted in megabytes per second) that can be moved past the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 applied per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the video 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 most pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.