GeForce 820M vs Radeon HD 4850 X2 512MB

Intro

Compare that to the Radeon HD 4850 X2 512MB, which has GPU clock speed of 625 MHz, and 512 MB of GDDR3 memory running at 993 MHz through a 256-bit bus. It also features 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)

GeForce 820M		15 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 235 Watts (1567%)

Memory Bandwidth

The Radeon HD 4850 X2 512MB should in theory perform quite a bit faster than the GeForce 820M in general. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 111104 (694%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (about 335%) faster with regards to AF than the GeForce 820M. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 38496 (335%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 4850 X2 512MB is the winner, by a large margin. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 17124 (595%)

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 (counted in megabytes per second) that can be transferred across the external memory interface in one second. It's calculated by multiplying the card's interface width by its memory speed. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 applied per second. This is worked out by multiplying the total texture units of the card by the core clock 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 applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.