GeForce GTX 870M vs Radeon HD 4870 2GB

Intro

Compare all that to the Radeon HD 4870 2GB, which uses a 55 nm design. AMD has clocked the core frequency at 750 MHz. The GDDR5 memory is set to run at a frequency of 900 MHz on this specific 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 GTX 870M		110 Watts
Radeon HD 4870 2GB		150 Watts
	Difference: 40 Watts (36%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4870 2GB should be 20% quicker than the GeForce GTX 870M overall, because of its greater data rate. (explain)

Radeon HD 4870 2GB		115200 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The GeForce GTX 870M will be a lot (more or less 251%) more effective at AF than the Radeon HD 4870 2GB. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 75392 (251%)

Pixel Rate

If running with a high resolution is important to you, then the GeForce GTX 870M is superior to the Radeon HD 4870 2GB, and very much so. (explain)

GeForce GTX 870M		22584 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 10584 (88%)

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 maximum amount of information (counted in MB per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 once 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 anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units of the card by the core 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 chip can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.