Radeon HD 4850 512MB vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, 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 memory bus, and makes use of a 28 nm design. It 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 4850 512MB		110 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 90 Watts (82%)

Memory Bandwidth

Theoretically, the Radeon HD 7950 3GB should be much faster than the Radeon HD 4850 512MB in general. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 176448 (278%)

Texel Rate

The Radeon HD 7950 3GB is quite a bit (approximately 258%) more effective at texture filtering than the Radeon HD 4850 512MB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 512MB		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 a better choice, and very much so. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 512MB		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 information (counted in megabytes per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.