GeForce 820M vs Radeon HD 7950 3GB

Intro

Compare those specs to the Radeon HD 7950 3GB, which has a clock speed of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also makes use of a 384-bit memory bus, and uses a 28 nm design. It is made up of 1792 SPUs, 112 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 185 Watts (1233%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7950 3GB should in theory be much superior to the GeForce 820M overall. (explain)

Radeon HD 7950 3GB		240000 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 224000 (1400%)

Texel Rate

The Radeon HD 7950 3GB should be quite a bit (about 679%) faster with regards to AF than the GeForce 820M. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 78096 (679%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7950 3GB is a better choice, by far. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 22724 (790%)

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: Memory bandwidth is the maximum amount of information (in units of megabytes per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. In the case of DDR RAM, it should 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 anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.