GeForce 920M vs GeForce GT 640 DDR3

Intro

Compare those specifications to the GeForce GT 640 DDR3, which comes with a clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also uses a 128-bit bus, and makes use of a 28 nm design. It is comprised of 384 SPUs, 32 Texture Address Units, and 16 Raster Operation 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 theoretically be quite a bit better than 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 should be just a bit (about 6%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

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

Pixel Rate

The GeForce GT 640 DDR3 should be quite a bit (approximately 89%) more effective at anti-aliasing than the GeForce 920M, and capable of handling higher resolutions more effectively. (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: Bandwidth is the max amount of data (measured in MB per second) that can be moved past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the video 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 amount of pixels that the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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 - the lower the bandwidth is, the lower the potential to get to the max fill rate.