Radeon HD 4850 512MB vs Radeon HD 7950 3GB

Intro

Compare those specifications to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has clocked the core speed at 800 MHz. The GDDR5 memory is set to run at a frequency of 1250 MHz on this model. It features 1792 SPUs as well as 112 TAUs and 32 ROPs.

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 speaking, the Radeon HD 7950 3GB should be 278% quicker than the Radeon HD 4850 512MB overall, because of its higher bandwidth. (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 should be a lot (more or less 258%) better at anisotropic 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

The Radeon HD 7950 3GB should be quite a bit (approximately 156%) better at FSAA than the Radeon HD 4850 512MB, and also capable of handling higher resolutions more effectively. (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 data (counted in MB per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card 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 clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.