Radeon HD 6770 1GB vs Radeon HD 7870

Intro

Compare those specifications to the Radeon HD 7870, which has a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also features 1280 SPUs, 80 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770 1GB		108 Watts
Radeon HD 7870		175 Watts
	Difference: 67 Watts (62%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7870 should in theory be a lot better than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 86400 (129%)

Texel Rate

The Radeon HD 7870 will be much (about 122%) faster with regards to texture filtering than the Radeon HD 6770 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 6770 1GB		36000 Mtexels/sec
	Difference: 44000 (122%)

Pixel Rate

The Radeon HD 7870 should be much (more or less 122%) more effective at AA than the Radeon HD 6770 1GB, and also capable of handling higher resolutions while still performing well. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 6770 1GB		14400 Mpixels/sec
	Difference: 17600 (122%)

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 (in units of MB per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If 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 higher screen 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 number of texture units of the card by the core speed of the chip. The higher this number, the better the graphics 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 that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number 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 fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.