Radeon HD 4850 2GB vs Radeon HD 6870

Intro

Compare those specifications to the Radeon HD 6870, which has clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs along with 56 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 2GB		110 Watts
Radeon HD 6870		151 Watts
	Difference: 41 Watts (37%)

Memory Bandwidth

In theory, the Radeon HD 6870 is 111% quicker than the Radeon HD 4850 2GB overall, due to its higher bandwidth. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 70848 (111%)

Texel Rate

The Radeon HD 6870 will be much (about 102%) better at texture filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 25400 (102%)

Pixel Rate

The Radeon HD 6870 should be quite a bit (more or less 188%) more effective at AA than the Radeon HD 4850 2GB, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 18800 (188%)

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 MB per second) that can be transferred past the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video 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 most pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core 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 fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.