Radeon HD 4870 X2 vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which has core clock speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6790		150 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 200 Watts (133%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 X2 will be 71% quicker than the Radeon HD 6790 overall, due to its higher data rate. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 6790		134400 MB/sec
	Difference: 96000 (71%)

Texel Rate

The Radeon HD 4870 X2 should be quite a bit (about 79%) better at texture filtering than the Radeon HD 6790. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 6790		33600 Mtexels/sec
	Difference: 26400 (79%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4870 X2 is superior to the Radeon HD 6790, by far. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 6790		13440 Mpixels/sec
	Difference: 10560 (79%)

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 (measured in MB per second) that can be transported past the external memory interface within a second. It is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 in one second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

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