Radeon HD 3850 X2 vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which comes with GPU clock speed of 950 MHz, and 3072 MB of GDDR5 memory set to run at 1500 MHz through a 384-bit bus. It also is comprised of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically, the Radeon HD 7990 should perform a lot faster than the Radeon HD 3850 X2 in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 470016 (443%)

Texel Rate

The Radeon HD 7990 should be much (approximately 1038%) faster with regards to AF than the Radeon HD 3850 X2. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 221824 (1038%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7990 is the winner, and very much so. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 3850 X2		21376 Mpixels/sec
	Difference: 39424 (184%)

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 information (counted in MB per second) that can be transferred over the external memory interface within a second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it should 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, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the graphics 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 can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.