GeForce 820M vs Radeon HD 4830 512MB

Intro

Compare those specs to the Radeon HD 4830 512MB, which features core speeds of 575 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 memory. It features 640(128x5) SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 4830 512MB		95 Watts
	Difference: 80 Watts (533%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4830 512MB should theoretically be a lot better than the GeForce 820M overall. (explain)

Radeon HD 4830 512MB		57600 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 41600 (260%)

Texel Rate

The Radeon HD 4830 512MB will be a lot (more or less 60%) more effective at anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 4830 512MB		18400 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 6896 (60%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4830 512MB is a better choice, by far. (explain)

Radeon HD 4830 512MB		9200 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 6324 (220%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card 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 Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.