Radeon HD 4850 X2 512MB vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which features a core clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 128-bit memory bus, and uses a 40 nm design. It features 800 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770		108 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 142 Watts (131%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 X2 512MB will be 89% quicker than the Radeon HD 6770 overall, due to its greater bandwidth. (explain)

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

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (approximately 39%) better at texture filtering than the Radeon HD 6770. (explain)

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

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4850 X2 512MB is the winner, by far. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 6770		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 (in units of MB per second) that can be transferred over the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core 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 fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.