Radeon HD 4850 X2 512MB vs Radeon HD 6770 1GB

Intro

Compare all of that to the Radeon HD 6770 1GB, which has a clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also uses a 128-bit memory bus, and makes use of a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation 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 512MB		250 Watts
	Difference: 142 Watts (131%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 512MB should in theory be much better than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 59904 (89%)

Texel Rate

The Radeon HD 4850 X2 512MB will be quite a bit (approximately 39%) more effective at anisotropic filtering than the Radeon HD 6770 1GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 14000 (39%)

Pixel Rate

The Radeon HD 4850 X2 512MB is a lot (approximately 39%) more effective at anti-aliasing than the Radeon HD 6770 1GB, and should be capable of handling higher resolutions better. (explain)

Radeon HD 4850 X2 512MB		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 largest amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the 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 amount of texture map elements (texels) that are applied per second. This number 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 graphics 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 that the graphics chip can possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.