Radeon HD 4870 X2 vs Radeon HD 4890 2GB

Intro

Compare all of that to the Radeon HD 4890 2GB, which comes with GPU core speed of 1000 MHz, and 2048 MB of GDDR5 memory running at 975 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 2GB		190 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 160 Watts (84%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 X2 should be 85% quicker than the Radeon HD 4890 2GB overall, because of its higher bandwidth. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 105600 (85%)

Texel Rate

The Radeon HD 4870 X2 should be quite a bit (approximately 50%) better at texture filtering than the Radeon HD 4890 2GB. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 20000 (50%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4870 X2 is a better choice, and very much so. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 8000 (50%)

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 (counted in megabytes per second) that can be moved across the external memory interface in one second. It is calculated by multiplying the bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR 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 worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics 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 can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.