Radeon HD 4830 512MB vs Radeon HD 4850 X2 1GB

Intro

Compare that to the Radeon HD 4850 X2 1GB, which makes use of a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 RAM works at a speed of 993 MHz on this specific model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 155 Watts (163%)

Memory Bandwidth

Performance-wise, the Radeon HD 4850 X2 1GB should in theory be much superior to the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 69504 (121%)

Texel Rate

The Radeon HD 4850 X2 1GB will be much (about 172%) better at anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 31600 (172%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4850 X2 1GB is a better choice, by far. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 4830 512MB		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: Bandwidth is the max amount of information (counted in megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 can be applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, 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 maximum amount of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.