Radeon HD 4850 1GB vs Radeon HD 7950 3GB

Intro

Compare that to the Radeon HD 7950 3GB, which features GPU core speed of 800 MHz, and 3072 MB of GDDR5 RAM set to run at 1250 MHz through a 384-bit bus. It also is made up of 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 4850 1GB		110 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 90 Watts (82%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 3GB should be 278% quicker than the Radeon HD 4850 1GB in general, because of its greater bandwidth. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 176448 (278%)

Texel Rate

The Radeon HD 7950 3GB will be a lot (about 258%) better at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 64600 (258%)

Pixel Rate

The Radeon HD 7950 3GB will be quite a bit (about 156%) more effective at anti-aliasing than the Radeon HD 4850 1GB, and also should be able to handle higher resolutions more effectively. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 1GB		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: Bandwidth is the max amount of information (measured in MB per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total texture units by the core speed of the chip. The better this number, the better the graphics 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 amount of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.