GeForce 820M vs Radeon HD 4870 512MB

Intro

Compare those specs to the Radeon HD 4870 512MB, which makes use of a 55 nm design. AMD has clocked the core speed at 750 MHz. The GDDR5 RAM runs at a frequency of 900 MHz on this particular model. It features 800(160x5) SPUs as well as 40 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 4870 512MB		150 Watts
	Difference: 135 Watts (900%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 512MB should be quite a bit faster than the GeForce 820M in general. (explain)

Radeon HD 4870 512MB		115200 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 99200 (620%)

Texel Rate

The Radeon HD 4870 512MB will be a lot (more or less 161%) faster with regards to anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 18496 (161%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4870 512MB is the winner, by far. (explain)

Radeon HD 4870 512MB		12000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 9124 (317%)

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 max amount of data (counted in MB per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's 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 amount of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can 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 the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.