GeForce 820M vs Radeon HD 3870 512MB

Intro

Compare all of that to the Radeon HD 3870 512MB, which comes with a core clock speed of 775 MHz and a GDDR3 memory speed of 900 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It features 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 91 Watts (607%)

Memory Bandwidth

The Radeon HD 3870 512MB should in theory perform a lot faster than the GeForce 820M overall. (explain)

Radeon HD 3870 512MB		57600 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 41600 (260%)

Texel Rate

The Radeon HD 3870 512MB is just a bit (about 8%) faster with regards to anisotropic filtering than the GeForce 820M. (explain)

Radeon HD 3870 512MB		12400 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 896 (8%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3870 512MB is the winner, by far. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 9524 (331%)

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 (measured in MB per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better 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 number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.