Radeon HD 4830 1GB vs Radeon HD 4850 X2 1GB

Intro

Compare those specs to the Radeon HD 4850 X2 1GB, which comes with core speeds of 625 MHz on the GPU, and 993 MHz on the 1024 MB of GDDR3 memory. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 155 Watts (163%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 1GB should theoretically be quite a bit better than the Radeon HD 4830 1GB overall. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 69504 (121%)

Texel Rate

The Radeon HD 4850 X2 1GB is much (approximately 172%) better at texture filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 31600 (172%)

Pixel Rate

The Radeon HD 4850 X2 1GB will be quite a bit (approximately 117%) more effective at full screen anti-aliasing than the Radeon HD 4830 1GB, and also should be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 10800 (117%)

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 (in units of MB per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the card's 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 4 instead. The better 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 amount of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video 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 maximum amount of pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the card's clock speed. 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 rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.