Radeon HD 6770 1GB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which uses a 28 nm design. AMD has clocked the core speed at 860 MHz. The GDDR5 memory is set to run at a frequency of 1200 MHz on this model. It features 1024 SPUs along with 64 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770 1GB		108 Watts
Radeon HD 7850		130 Watts
	Difference: 22 Watts (20%)

Memory Bandwidth

Performance-wise, the Radeon HD 7850 should in theory be much superior to the Radeon HD 6770 1GB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 86400 (129%)

Texel Rate

The Radeon HD 7850 will be a lot (about 53%) faster with regards to AF than the Radeon HD 6770 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 19040 (53%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7850 is the winner, and very much so. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 13120 (91%)

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 (in units of megabytes per second) that can be transported past the external memory interface within a second. It's worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

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