GeForce GTX 870M vs Radeon HD 4870 X2

Intro

Compare all of that to the Radeon HD 4870 X2, which makes use of a 55 nm design. AMD has set the core speed at 750 MHz. The GDDR5 memory is set to run at a frequency of 900 MHz on this particular model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 870M		110 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 240 Watts (218%)

Memory Bandwidth

In theory, the Radeon HD 4870 X2 will be 140% quicker than the GeForce GTX 870M overall, due to its higher bandwidth. (explain)

Radeon HD 4870 X2		230400 MB/sec
GeForce GTX 870M		96000 MB/sec
	Difference: 134400 (140%)

Texel Rate

The GeForce GTX 870M will be quite a bit (about 76%) faster with regards to AF than the Radeon HD 4870 X2. (explain)

GeForce GTX 870M		105392 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 45392 (76%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4870 X2 is a better choice, but it probably won't make a huge difference. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
GeForce GTX 870M		22584 Mpixels/sec
	Difference: 1416 (6%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result 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, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record 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 core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. 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 ability to get to the maximum fill rate.