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

Intro

Compare those specs to the Radeon HD 6770 1GB, which comes with core speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

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% faster than the Radeon HD 6770 1GB in general, because of its higher 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 a lot (more or less 39%) more effective 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

The Radeon HD 4850 X2 1GB will be quite a bit (about 39%) more effective at AA than the Radeon HD 6770 1GB, and also able to handle higher resolutions while still performing well. (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: Memory bandwidth is the maximum amount of information (measured in megabytes per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 number is worked out by multiplying the total texture units of the card by the core clock 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 in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.