Radeon HD 3850 X2 vs Radeon HD 4890 2GB

Intro

Compare those specifications to the Radeon HD 4890 2GB, which comes with GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 memory set to run at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 4890 2GB should in theory be a small bit better than the Radeon HD 3850 X2 in general. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 18816 (18%)

Texel Rate

The Radeon HD 4890 2GB should be a lot (about 87%) faster with regards to texture filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 18624 (87%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3850 X2 is superior to the Radeon HD 4890 2GB, by a large margin. (explain)

Radeon HD 3850 X2		21376 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 5376 (34%)

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 (counted in megabytes per second) that can be transported across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that 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 number of Render Output Units by the the core speed of the card. 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 of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.