Radeon HD 3870 1GB vs Radeon HD 6770 1GB

Intro

Compare that to the Radeon HD 6770 1GB, which makes use of a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 memory is set to run at a speed of 1050 MHz on this model. It features 800 SPUs along with 40 TAUs and 16 Rasterization Operator 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

In theory, the Radeon HD 3870 1GB should be 7% faster than the Radeon HD 6770 1GB in general, due to its greater data rate. (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 quite a bit (approximately 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 will be just a bit (more or less 16%) more effective at AA than the Radeon HD 3870 1GB, and also will be capable of handling 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: Memory bandwidth is the largest amount of information (in units of MB per second) that can be transported over the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, 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 amount of texture map elements (texels) that are applied per second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. 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 rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.