Radeon HD 4870 512MB vs Radeon HD 7950

Intro

Compare that to the Radeon HD 7950, which has a core clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 384-bit bus, and makes use of a 28 nm design. It features 1792 SPUs, 112 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 7950		200 Watts
	Difference: 50 Watts (33%)

Memory Bandwidth

The Radeon HD 7950, in theory, should perform much faster than the Radeon HD 4870 512MB in general. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon HD 7950 is much (approximately 199%) better at texture filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 59600 (199%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 7950 is a better choice, by a large margin. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4870 512MB		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: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.