Radeon HD 3870 512MB vs Radeon HD 4770

Intro

Compare those specifications to the Radeon HD 4770, which features GPU core speed of 750 MHz, and 512 MB of GDDR5 memory set to run at 800 MHz through a 128-bit bus. It also 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

In theory, the Radeon HD 3870 512MB will be 13% faster than the Radeon HD 4770 overall, due to its greater data rate. (explain)

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

Texel Rate

The Radeon HD 4770 should be quite a bit (more or less 94%) better at texture 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 running with high levels of AA is important to you, then the Radeon HD 3870 512MB is the winner, but it probably won't make a huge difference. (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: Memory bandwidth is the maximum amount of information (counted in megabytes per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, 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 maximum amount of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.