Radeon HD 4870 X2 vs Radeon HD 5850

Intro

Compare all that to the Radeon HD 5850, which comes with GPU core speed of 725 MHz, and 1024 MB of GDDR5 memory running at 1000 MHz through a 256-bit bus. It also is comprised of 1440(288x5) Stream Processors, 72 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5850		151 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 199 Watts (132%)

Memory Bandwidth

The Radeon HD 4870 X2 should in theory be quite a bit faster than the Radeon HD 5850 in general. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 5850		128000 MB/sec
	Difference: 102400 (80%)

Texel Rate

The Radeon HD 4870 X2 is a bit (about 15%) faster with regards to AF than the Radeon HD 5850. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 5850		52200 Mtexels/sec
	Difference: 7800 (15%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4870 X2 is the winner, though only just barely. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 5850		23200 Mpixels/sec
	Difference: 800 (3%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

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. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.