GeForce 825M vs Radeon HD 4790

Intro

Compare all that to the Radeon HD 4790, which comes with a core clock speed of 600 MHz and a GDDR5 memory frequency of 800 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It is comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4790 is 611% faster than the GeForce 825M in general, because of its higher data rate. (explain)

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

Texel Rate

The Radeon HD 4790 will be much (about 41%) faster with regards to texture filtering 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 much (about 41%) more effective at full screen anti-aliasing than the GeForce 825M, and able to handle higher screen resolutions without slowing down too much. (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: Bandwidth is the max amount of data (in units of megabytes per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.