GeForce 825M vs Radeon HD 4790

Intro

Compare that to the Radeon HD 4790, which features GPU clock speed of 600 MHz, and 512 MB of GDDR5 memory set to run at 800 MHz through a 256-bit bus. It also is comprised of 640(128x5) SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4790 should perform much faster than the GeForce 825M in general. (explain)

Radeon HD 4790		102400 MB/sec
GeForce 825M		14400 MB/sec
	Difference: 88000 (611%)

Texel Rate

The Radeon HD 4790 is much (more or less 41%) faster with regards to AF than the GeForce 825M. (explain)

Radeon HD 4790		19200 Mtexels/sec
GeForce 825M		13600 Mtexels/sec
	Difference: 5600 (41%)

Pixel Rate

The Radeon HD 4790 will be quite a bit (more or less 41%) more effective at AA than the GeForce 825M, and also should be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 4790		9600 Mpixels/sec
GeForce 825M		6800 Mpixels/sec
	Difference: 2800 (41%)

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 information (counted in megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 once 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.