Radeon HD 4870 512MB vs Radeon HD 7970

Intro

Compare those specifications to the Radeon HD 7970, which has GPU core speed of 925 MHz, and 3072 MB of GDDR5 memory running at 1375 MHz through a 384-bit bus. It also features 2048 Stream Processors, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 7970		250 Watts
	Difference: 100 Watts (67%)

Memory Bandwidth

The Radeon HD 7970 should theoretically be much faster than the Radeon HD 4870 512MB overall. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 148800 (129%)

Texel Rate

The Radeon HD 7970 should be much (about 295%) more effective at texture filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 88400 (295%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7970 is a better choice, and very much so. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 17600 (147%)

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 largest amount of information (in units of megabytes per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher 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 number of texture map elements (texels) that are processed per second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units 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 is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.