Radeon HD 4850 X2 1GB vs Radeon HD 6770 1GB

Intro

Compare that to the Radeon HD 6770 1GB, which makes use of a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 RAM is set to run at a speed of 1050 MHz on this particular model. It features 800 SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770 1GB		108 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 142 Watts (131%)

Memory Bandwidth

In theory, the Radeon HD 4850 X2 1GB should be 89% quicker than the Radeon HD 6770 1GB in general, due to its greater bandwidth. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 59904 (89%)

Texel Rate

The Radeon HD 4850 X2 1GB is quite a bit (more or less 39%) better at texture filtering than the Radeon HD 6770 1GB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 14000 (39%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 1GB is a better choice, by a large margin. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 5600 (39%)

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: Bandwidth is the largest amount of information (counted in megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.