Radeon HD 4850 2GB vs Radeon HD 6770

Intro

Compare all of that to the Radeon HD 6770, which uses a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 memory is set to run at a frequency of 1050 MHz on this specific card. It features 800 SPUs as well as 40 TAUs 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 should in theory be a small 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 is much (more or less 44%) more effective at texture filtering 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 will be much (about 44%) faster with regards to AA than the Radeon HD 4850 2GB, and should be capable of handling higher 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: Bandwidth is the largest amount of information (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure 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 graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.