GeForce 920M vs GeForce GT 640 DDR3

Intro

Compare all that to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has set the core speed at 900 MHz. The DDR3 RAM is set to run at a frequency of 1782 MHz on this card. It features 384 SPUs as well as 32 Texture Address Units and 16 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 GT 640 DDR3		1560 points
GeForce 920M		1180 points
	Difference: 380 (32%)

Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the GeForce GT 640 DDR3 should in theory be a lot superior to the GeForce 920M overall. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 920M		14400 MB/sec
	Difference: 42624 (296%)

Texel Rate

The GeForce 920M will be a small bit (more or less 6%) better at AF than the GeForce GT 640 DDR3. (explain)

GeForce 920M		30528 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 1728 (6%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GT 640 DDR3 is a better choice, and very much so. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 920M		7632 Mpixels/sec
	Difference: 6768 (89%)

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 largest amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. The number is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 applied in one second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.