GeForce GTX 870M vs Radeon HD 4790

Intro

Compare all that to the Radeon HD 4790, which comes with GPU core speed of 600 MHz, and 512 MB of GDDR5 memory running at 800 MHz through a 256-bit bus. It also is made up of 640(128x5) Stream Processors, 32 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4790 should in theory be just a bit faster than the GeForce GTX 870M in general. (explain)

Radeon HD 4790		102400 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 6400 (7%)

Texel Rate

The GeForce GTX 870M will be much (more or less 449%) faster with regards to AF than the Radeon HD 4790. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 86192 (449%)

Pixel Rate

The GeForce GTX 870M should be quite a bit (about 135%) faster with regards to full screen anti-aliasing than the Radeon HD 4790, and also should be capable of handling higher screen resolutions more effectively. (explain)

GeForce GTX 870M		22584 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 12984 (135%)

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 information (measured in MB per second) that can be transported over the external memory interface in one second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 amount of texture map elements (texels) that can be processed in one second. This figure is worked out by multiplying the total number of texture units by the core clock 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 processed in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.