GeForce 820M vs Radeon HD 3690/3830

Intro

Compare that to the Radeon HD 3690/3830, which features core speeds of 668 MHz on the GPU, and 828 MHz on the 256 MB of GDDR3 RAM. It features 320(64x5) SPUs as well as 16 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 3690/3830		75 Watts
	Difference: 60 Watts (400%)

Memory Bandwidth

As far as performance goes, the Radeon HD 3690/3830 should in theory be quite a bit better than the GeForce 820M in general. (explain)

Radeon HD 3690/3830		26496 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 10496 (66%)

Texel Rate

The GeForce 820M should be just a bit (more or less 8%) more effective at AF than the Radeon HD 3690/3830. (explain)

GeForce 820M		11504 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 816 (8%)

Pixel Rate

The Radeon HD 3690/3830 will be much (more or less 272%) better at AA than the GeForce 820M, and should be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 3690/3830		10688 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 7812 (272%)

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 max amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster 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 applied in one second. This 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 video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.