GeForce 920M vs GeForce GT 640 DDR3

Intro

Compare that to the GeForce GT 640 DDR3, which comes with core speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 RAM. It features 384 SPUs along with 32 TAUs 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

The GeForce GT 640 DDR3 should theoretically be a lot faster than the GeForce 920M in general. (explain)

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

Texel Rate

The GeForce 920M should be a small bit (more or less 6%) faster with regards to 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 will be a lot (more or less 89%) better at FSAA than the GeForce 920M, and will be capable of handling higher resolutions while still performing well. (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 (counted in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory speed. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the card will be at 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 that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.