Radeon HD 4850 2GB vs Radeon HD 7950 3GB

Intro

Compare all that to the Radeon HD 7950 3GB, which uses a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory runs at a speed of 1250 MHz on this specific card. It features 1792 SPUs along with 112 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 2GB		110 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 90 Watts (82%)

Memory Bandwidth

In theory, the Radeon HD 7950 3GB should be quite a bit faster than the Radeon HD 4850 2GB in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 176448 (278%)

Texel Rate

The Radeon HD 7950 3GB should be quite a bit (about 258%) better at anisotropic filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 64600 (258%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7950 3GB is the winner, by far. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 15600 (156%)

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 largest amount of data (in units of MB per second) that can be transferred across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 once 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, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.