Radeon HD 4850 2GB vs Radeon HD 4850 X2 1GB

Intro

Compare that 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 RAM. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.

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 1GB		250 Watts
	Difference: 140 Watts (127%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 X2 1GB will be 100% faster than the Radeon HD 4850 2GB overall, due to its higher data rate. (explain)

Radeon HD 4850 X2 1GB		127104 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 63552 (100%)

Texel Rate

The Radeon HD 4850 X2 1GB is much (approximately 100%) faster with regards to AF than the Radeon HD 4850 2GB. (explain)

Radeon HD 4850 X2 1GB		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 1GB is a better choice, by far. (explain)

Radeon HD 4850 X2 1GB		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 (counted in MB per second) that can be transported over the external memory interface in a second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 number of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at handling 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 that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.