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

Intro

Compare those specifications to the Radeon HD 4850 X2 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 memory runs at a speed 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 quite a bit faster than the Radeon HD 4850 2GB in general. (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 much (about 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 much (approximately 100%) more effective at full screen anti-aliasing than the Radeon HD 4850 2GB, and should be able to handle higher resolutions more effectively. (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 largest amount of data (in units of MB per second) that can be transported over the external memory interface in one second. It's calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR 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 worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels 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 number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.