Radeon HD 4850 2GB vs Radeon HD 4850 X2 512MB

Intro

Compare all that to the Radeon HD 4850 X2 512MB, which has a GPU core clock speed of 625 MHz, and 512 MB of GDDR3 memory set to run at 993 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

Power Consumption (Max TDP)

Radeon HD 4850 2GB		110 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 140 Watts (127%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4850 X2 512MB should theoretically be much superior to the Radeon HD 4850 2GB overall. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 63552 (100%)

Texel Rate

The Radeon HD 4850 X2 512MB will be quite a bit (more or less 100%) better at anisotropic filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 25000 (100%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4850 X2 512MB is a better choice, by far. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 4850 2GB		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: Bandwidth is the maximum amount of data (in units of MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, it must 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 AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core 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 quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.