Radeon HD 3850 X2 vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which has GPU core speed of 840 MHz, and 1024 MB of GDDR5 RAM running at 1050 MHz through a 256-bit bus. It also is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 6790 should be 27% quicker than the Radeon HD 3850 X2 in general, due to its greater data rate. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 28416 (27%)

Texel Rate

The Radeon HD 6790 should be quite a bit (approximately 57%) faster with regards to anisotropic filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 12224 (57%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 3850 X2 is the winner, and very much so. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 6790		13440 Mpixels/sec
	Difference: 7936 (59%)

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 max amount of data (in units of megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the bus 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 bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.