Radeon HD 4830 1GB vs Radeon HD 4850 X2 512MB

Intro

Compare those specifications to the Radeon HD 4850 X2 512MB, which has a clock speed of 625 MHz and a GDDR3 memory frequency of 993 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is comprised of 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 4830 1GB		95 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 155 Watts (163%)

Memory Bandwidth

In theory, the Radeon HD 4850 X2 512MB will be 121% quicker than the Radeon HD 4830 1GB in general, because of its higher bandwidth. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 69504 (121%)

Texel Rate

The Radeon HD 4850 X2 512MB should be a lot (more or less 172%) better at anisotropic filtering than the Radeon HD 4830 1GB. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 31600 (172%)

Pixel Rate

The Radeon HD 4850 X2 512MB is much (approximately 117%) more effective at AA than the Radeon HD 4830 1GB, and able to handle higher resolutions more effectively. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 10800 (117%)

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 max amount of information (in units of megabytes per second) that can be moved over the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 once 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, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on 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 ability to get to the maximum fill rate.