Radeon HD 4870 1GB vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which features a clock speed of 1000 MHz and a GDDR5 memory speed of 1200 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It is made up of 1280 SPUs, 80 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 1GB		150 Watts
Radeon HD 7870		175 Watts
	Difference: 25 Watts (17%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7870 should theoretically be a lot better than the Radeon HD 4870 1GB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 38400 (33%)

Texel Rate

The Radeon HD 7870 should be much (more or less 167%) faster with regards to anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 50000 (167%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7870 is the winner, by far. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 20000 (167%)

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 (counted in megabytes per second) that can be transferred across the external memory interface within a second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. 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 amount of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units by the core clock 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 applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.