GeForce 830M vs GeForce GT 640 DDR3

Intro

Compare all of that to the GeForce GT 640 DDR3, which comes with clock speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 memory. It features 384 SPUs along with 32 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 830M		25 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 40 Watts (160%)

Memory Bandwidth

The GeForce GT 640 DDR3, in theory, should be quite a bit faster than the GeForce 830M in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
GeForce 830M		14400 MB/sec
	Difference: 42624 (296%)

Texel Rate

The GeForce GT 640 DDR3 will be quite a bit (about 75%) better at texture filtering than the GeForce 830M. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
GeForce 830M		16464 Mtexels/sec
	Difference: 12336 (75%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is a better choice, by a large margin. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
GeForce 830M		8232 Mpixels/sec
	Difference: 6168 (75%)

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 max amount of data (measured in MB per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's 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 are processed per second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core clock speed. 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 rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.