Radeon HD 3870 1GB vs Radeon HD 7770

Intro

Compare all that to the Radeon HD 7770, which comes with clock speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 RAM. It features 640 SPUs along with 40 TAUs 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 1GB		106 Watts
	Difference: 26 Watts (33%)

Memory Bandwidth

Both cards have exactly the same bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

The Radeon HD 7770 will be much (more or less 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 running with a high resolution is important to you, then the Radeon HD 7770 is superior to the Radeon HD 3870 1GB, by far. (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: Memory bandwidth is the largest amount of data (counted in megabytes per second) that can be transported across the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

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