Radeon HD 4790 vs Radeon HD 4850 X2 512MB

Intro

Compare those specs to the Radeon HD 4850 X2 512MB, which comes with core clock speeds of 625 MHz on the GPU, and 993 MHz on the 512 MB of GDDR3 memory. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4850 X2 512MB should be 24% quicker than the Radeon HD 4790 overall, due to its higher bandwidth. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 24704 (24%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (more or less 160%) more effective at AF than the Radeon HD 4790. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 30800 (160%)

Pixel Rate

The Radeon HD 4850 X2 512MB will be much (more or less 108%) faster with regards to AA than the Radeon HD 4790, and also will be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 10400 (108%)

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 data (counted in megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This number is calculated 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 applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.