Radeon HD 4850 2GB vs Radeon HD 6770

Intro

Compare all that to the Radeon HD 6770, which comes with clock speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 memory. It features 800 SPUs as well as 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 2GB		110 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

The Radeon HD 6770, in theory, should be a little bit faster than the Radeon HD 4850 2GB overall. (explain)

Radeon HD 6770		67200 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 3648 (6%)

Texel Rate

The Radeon HD 6770 should be much (approximately 44%) faster with regards to AF than the Radeon HD 4850 2GB. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 11000 (44%)

Pixel Rate

The Radeon HD 6770 is quite a bit (more or less 44%) faster with regards to AA than the Radeon HD 4850 2GB, and also will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 4400 (44%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (measured in MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs 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 output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.