Radeon HD 4850 1GB vs Radeon HD 6870

Intro

Compare that to the Radeon HD 6870, which uses a 40 nm design. AMD has set the core speed at 900 MHz. The GDDR5 RAM runs at a speed of 1050 MHz on this particular model. It features 1120 SPUs as well as 56 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 6870		151 Watts
	Difference: 41 Watts (37%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6870 should in theory be a lot better than the Radeon HD 4850 1GB in general. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 70848 (111%)

Texel Rate

The Radeon HD 6870 is quite a bit (about 102%) better at texture filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 25400 (102%)

Pixel Rate

The Radeon HD 6870 will be a lot (about 188%) better at full screen anti-aliasing than the Radeon HD 4850 1GB, and also capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4850 1GB		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 information (measured in megabytes per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it should 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 higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units 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 also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.