GeForce GTX 870M vs Radeon HD 4870 512MB

Intro

Compare all of that to the Radeon HD 4870 512MB, which features a core clock speed of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 870M		110 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 40 Watts (36%)

Memory Bandwidth

In theory, the Radeon HD 4870 512MB is 20% faster than the GeForce GTX 870M in general, because of its higher bandwidth. (explain)

Radeon HD 4870 512MB		115200 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The GeForce GTX 870M should be quite a bit (more or less 251%) better at AF than the Radeon HD 4870 512MB. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 75392 (251%)

Pixel Rate

The GeForce GTX 870M should be much (approximately 88%) more effective at anti-aliasing than the Radeon HD 4870 512MB, and also able to handle higher screen resolutions more effectively. (explain)

GeForce GTX 870M		22584 Mpixels/sec
Radeon HD 4870 512MB		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: Memory bandwidth is the maximum amount of information (measured in megabytes per second) that can be transferred over the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka 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 of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.