Radeon HD 3870 512MB vs Radeon HD 4770

Intro

Compare those specifications to the Radeon HD 4770, which features a clock speed of 750 MHz and a GDDR5 memory frequency of 800 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It is comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 26 Watts (33%)

Memory Bandwidth

The Radeon HD 3870 512MB should in theory perform a little bit faster than the Radeon HD 4770 in general. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 6400 (13%)

Texel Rate

The Radeon HD 4770 is quite a bit (more or less 94%) better at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4770		24000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 11600 (94%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 3870 512MB is the winner, but only just. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 400 (3%)

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 maximum amount of information (counted in MB per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units of the card by the core 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 in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.