GeForce GT 640 DDR3 vs GeForce GTX 870M

Intro

Compare all that to the GeForce GTX 870M, which uses a 28 nm design. nVidia has set the core frequency at 941 MHz. The GDDR5 RAM runs at a speed of 1000 MHz on this model. It features 1344 SPUs as well as 112 Texture Address Units and 24 Rasterization Operator Units.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

GeForce GTX 870M		4770 points
GeForce GT 640 DDR3		1560 points
	Difference: 3210 (206%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 870M		110 Watts
	Difference: 45 Watts (69%)

Memory Bandwidth

The GeForce GTX 870M should in theory be quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)

GeForce GTX 870M		96000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 38976 (68%)

Texel Rate

The GeForce GTX 870M should be a lot (more or less 266%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

GeForce GTX 870M		105392 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 76592 (266%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 870M is superior to the GeForce GT 640 DDR3, by far. (explain)

GeForce GTX 870M		22584 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 8184 (57%)

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 data (measured in megabytes per second) that can be moved over the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines 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 output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.