Radeon HD 4850 X2 1GB vs Radeon HD 7950 3GB

Intro

Compare that to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory runs at a frequency of 1250 MHz on this model. 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 7950 3GB		200 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 50 Watts (25%)

Memory Bandwidth

The Radeon HD 7950 3GB should theoretically perform quite a bit faster than the Radeon HD 4850 X2 1GB overall. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 112896 (89%)

Texel Rate

The Radeon HD 7950 3GB should be a lot (about 79%) better at anisotropic filtering than the Radeon HD 4850 X2 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 39600 (79%)

Pixel Rate

The Radeon HD 7950 3GB is much (approximately 28%) faster with regards to FSAA than the Radeon HD 4850 X2 1GB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 5600 (28%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (measured in megabytes per second) that can be transferred across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better 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 number of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.