Radeon HD 4850 512MB vs Radeon HD 6870

Intro

Compare those specifications to the Radeon HD 6870, which uses a 40 nm design. AMD has clocked the core frequency at 900 MHz. The GDDR5 RAM is set to run at a frequency of 1050 MHz on this particular card. It features 1120 SPUs as well as 56 Texture Address Units and 32 Rasterization Operator 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 be 111% quicker than the Radeon HD 4850 512MB overall, because of its greater data rate. (explain)

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

Texel Rate

The Radeon HD 6870 is a lot (about 102%) more effective at texture 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 running with high levels of AA is important to you, then the Radeon HD 6870 is a better choice, 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: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total number of texture units of the card by the core 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 in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core speed of the card. 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 rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.