Radeon HD 3870 1GB vs Radeon HD 6770 1GB

Intro

Compare all of that to the Radeon HD 6770 1GB, which comes with a core clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 128-bit memory bus, and uses a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon HD 6770 1GB		108 Watts
	Difference: 2 Watts (2%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 1GB should perform a bit faster than the Radeon HD 6770 1GB overall. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 6770 1GB		67200 MB/sec
	Difference: 4800 (7%)

Texel Rate

The Radeon HD 6770 1GB will be a lot (about 190%) better at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 23600 (190%)

Pixel Rate

The Radeon HD 6770 1GB is just a bit (approximately 16%) faster with regards to AA than the Radeon HD 3870 1GB, and also able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 6770 1GB		14400 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 2000 (16%)

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 data (measured in megabytes per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

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