Radeon HD 4870 1GB vs Radeon HD 5670

Intro

Compare those specs to the Radeon HD 5670, which comes with GPU clock speed of 775 MHz, and 1024 MB of GDDR5 memory set to run at 1000 MHz through a 128-bit bus. It also is made up of 400(80x5) Stream Processors, 20 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5670		61 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 89 Watts (146%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 1GB should perform much faster than the Radeon HD 5670 in general. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 5670		64000 MB/sec
	Difference: 51200 (80%)

Texel Rate

The Radeon HD 4870 1GB is a lot (approximately 94%) better at AF than the Radeon HD 5670. (explain)

Radeon HD 4870 1GB		30000 Mtexels/sec
Radeon HD 5670		15500 Mtexels/sec
	Difference: 14500 (94%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 4870 1GB is a better choice, by a large margin. (explain)

Radeon HD 4870 1GB		12000 Mpixels/sec
Radeon HD 5670		6200 Mpixels/sec
	Difference: 5800 (94%)

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 (in units of MB per second) that can be transferred across the external memory interface within a second. It's worked out by multiplying the card's interface width by its memory clock speed. In the case of 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 high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.