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

Intro

Compare that to the Radeon HD 4850 X2 1GB, which has a clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 512MB		110 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 140 Watts (127%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 1GB should theoretically be quite a bit better than the Radeon HD 4850 512MB in general. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 63552 (100%)

Texel Rate

The Radeon HD 4850 X2 1GB is quite a bit (about 100%) faster with regards to texture filtering than the Radeon HD 4850 512MB. (explain)

Radeon HD 4850 X2 1GB		50000 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 25000 (100%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4850 X2 1GB is the winner, and very much so. (explain)

Radeon HD 4850 X2 1GB		20000 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 10000 (100%)

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 (measured in MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the 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 core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.