Radeon HD 6770 1GB vs Radeon HD 7850

Intro

Compare those specifications to the Radeon HD 7850, which has a clock speed of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit memory bus, and makes use of a 28 nm design. It features 1024 SPUs, 64 TAUs, 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

Theoretically speaking, the Radeon HD 7850 should be 129% quicker than the Radeon HD 6770 1GB overall, due to its higher data rate. (explain)

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

Texel Rate

The Radeon HD 7850 is a lot (more or less 53%) better at anisotropic filtering 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 running with a high resolution is important to you, then the Radeon HD 7850 is a better choice, 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 max amount of data (counted in MB per second) that can be transported across the external memory interface in one second. It's worked out 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 4 instead. The higher the card's memory bandwidth, 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 applied per second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.