Radeon HD 4850 512MB vs Radeon HD 6870

Intro

Compare that to the Radeon HD 6870, which has a core clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 1120 SPUs, 56 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 512MB		110 Watts
Radeon HD 6870		151 Watts
	Difference: 41 Watts (37%)

Memory Bandwidth

In theory, the Radeon HD 6870 should perform a lot faster than the Radeon HD 4850 512MB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 70848 (111%)

Texel Rate

The Radeon HD 6870 is quite a bit (approximately 102%) faster with regards to anisotropic filtering than the Radeon HD 4850 512MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 25400 (102%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6870 is superior to the Radeon HD 4850 512MB, by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4850 512MB		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: Bandwidth is the max amount of data (measured in MB per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the 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 per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.