Radeon HD 3870 1GB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which uses a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM runs at a frequency of 1125 MHz on this model. It features 640 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 7770		80 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 26 Watts (33%)

Memory Bandwidth

Both cards have the exact same bandwidth, so theoretically they should have identical performance. (explain)

Texel Rate

The Radeon HD 7770 will be much (about 223%) faster with regards to AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 27600 (223%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7770 is a better choice, by a large margin. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 3870 1GB		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 max amount of data (measured in megabytes per second) that can be transferred across the external memory interface within a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.