Radeon HD 4870 X2 vs Radeon HD 5870

Intro

Compare those specifications to the Radeon HD 5870, which makes use of a 40 nm design. AMD has set the core speed at 850 MHz. The GDDR5 memory is set to run at a speed of 1200 MHz on this model. It features 1600(320x5) SPUs along with 80 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5870		188 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 162 Watts (86%)

Memory Bandwidth

Theoretically, the Radeon HD 4870 X2 should perform a lot faster than the Radeon HD 5870 in general. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 5870		153600 MB/sec
	Difference: 76800 (50%)

Texel Rate

The Radeon HD 5870 should be a bit (approximately 13%) more effective at texture filtering than the Radeon HD 4870 X2. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 8000 (13%)

Pixel Rate

The Radeon HD 5870 is just a bit (approximately 13%) faster with regards to FSAA than the Radeon HD 4870 X2, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 5870		27200 Mpixels/sec
Radeon HD 4870 X2		24000 Mpixels/sec
	Difference: 3200 (13%)

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 maximum amount of information (in units of MB per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.