Radeon HD 3850 X2 vs Radeon HD 4790

Intro

Compare that to the Radeon HD 4790, which features GPU core speed of 600 MHz, and 512 MB of GDDR5 memory running at 800 MHz through a 256-bit bus. It also features 640(128x5) SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon HD 3850 X2 should be a small bit faster than the Radeon HD 4790 overall. (explain)

Radeon HD 3850 X2		105984 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 3584 (4%)

Texel Rate

The Radeon HD 3850 X2 should be a small bit (more or less 11%) better at anisotropic filtering than the Radeon HD 4790. (explain)

Radeon HD 3850 X2		21376 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 2176 (11%)

Pixel Rate

The Radeon HD 3850 X2 will be a lot (approximately 123%) more effective at FSAA than the Radeon HD 4790, and should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 11776 (123%)

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 transferred over the external memory interface in a second. The number is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total amount of texture units of the card 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 applied in one second.

Pixel Rate: Pixel rate is the maximum number of 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 calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.