Radeon HD 4870 1GB vs Radeon HD 7870

Intro

Compare that to the Radeon HD 7870, which has a clock speed of 1000 MHz and a GDDR5 memory speed of 1200 MHz. It also makes use of a 256-bit bus, and uses a 28 nm design. It features 1280 SPUs, 80 Texture Address Units, and 32 ROPs.

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

The Radeon HD 7870, in theory, should be quite a bit faster than the Radeon HD 4870 1GB in general. (explain)

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

Texel Rate

The Radeon HD 7870 is quite a bit (more or less 167%) better at AF 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 running with a high resolution is important to you, then the Radeon HD 7870 is the winner, by a large margin. (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: Memory bandwidth is the largest amount of data (measured in megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the bus width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster 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 amount of texture map elements (texels) that are processed per second. This is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the card will be at 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 the video card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.