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

Intro

Compare all of that to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has clocked the core frequency at 625 MHz. The GDDR3 RAM is set to run at a frequency of 993 MHz on this specific card. 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

In theory, the Radeon HD 4850 X2 1GB should be 100% quicker 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 will be quite a bit (more or less 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

The Radeon HD 4850 X2 1GB should be quite a bit (more or less 100%) more effective at anti-aliasing than the Radeon HD 4850 2GB, and also should be capable of handling higher screen resolutions without losing too much performance. (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: Memory bandwidth is the largest amount of information (counted in megabytes per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 amount of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.