GeForce GTX 870M vs Radeon HD 4870 2GB

Intro

Compare those specs to the Radeon HD 4870 2GB, which features a core clock speed of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It is comprised of 800(160x5) SPUs, 40 TAUs, 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

Performance-wise, the Radeon HD 4870 2GB should theoretically be a bit superior to the GeForce GTX 870M overall. (explain)

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

Texel Rate

The GeForce GTX 870M is much (about 251%) better at anisotropic filtering 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: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.