Radeon HD 4870 2GB vs Radeon HD 7950

Intro

Compare all that to the Radeon HD 7950, which has GPU core speed of 800 MHz, and 1536 MB of GDDR5 memory set to run at 1250 MHz through a 384-bit bus. It also features 1792 SPUs, 112 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon HD 7950		200 Watts
	Difference: 50 Watts (33%)

Memory Bandwidth

Theoretically, the Radeon HD 7950 should be much faster than the Radeon HD 4870 2GB overall. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon HD 7950 is much (more or less 199%) faster with regards to texture filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 59600 (199%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7950 is the winner, by a large margin. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4870 2GB		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 (counted in MB per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the video 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 amount of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the clock 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 rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.