Radeon HD 3850 X2 vs Radeon HD 4870 X2

Intro

Compare all that to the Radeon HD 4870 X2, which has GPU core speed of 750 MHz, and 1024 MB of GDDR5 RAM set to run at 900 MHz through a 256-bit bus. It also is made up 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

In theory, the Radeon HD 4870 X2 should perform quite a bit faster than the Radeon HD 3850 X2 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 3850 X2		105984 MB/sec
	Difference: 124416 (117%)

Texel Rate

The Radeon HD 4870 X2 will be a lot (about 181%) faster with regards to texture filtering than the Radeon HD 3850 X2. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 3850 X2		21376 Mtexels/sec
	Difference: 38624 (181%)

Pixel Rate

The Radeon HD 4870 X2 will be a small bit (more or less 12%) more effective at FSAA than the Radeon HD 3850 X2, and should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 3850 X2		21376 Mpixels/sec
	Difference: 2624 (12%)

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: Bandwidth is the largest amount of data (measured in megabytes per second) that can be transported past the external memory interface in a second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.