Radeon HD 3870 512MB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which has a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also is made up of 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 26 Watts (33%)

Memory Bandwidth

In theory, the Radeon HD 7770 should perform much faster than the Radeon HD 3870 512MB overall. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon HD 7770 is a lot (approximately 223%) more effective at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 27600 (223%)

Pixel Rate

The Radeon HD 7770 is a lot (more or less 29%) better at AA than the Radeon HD 3870 512MB, and also able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 3870 512MB		12400 Mpixels/sec
	Difference: 3600 (29%)

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 (counted in MB per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the video 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 write to its local memory per second - measured in millions of pixels per second. The number 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 fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.