GeForce 830M vs GeForce 840M

Intro

Compare those specifications to the GeForce 840M, which comes with GPU core speed of 1029 MHz, and 2048 MB of DDR3 memory running at 1000 MHz through a 64-bit bus. It also is comprised of 384 Stream Processors, 24 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 830M		25 Watts
GeForce 840M		30 Watts
	Difference: 5 Watts (20%)

Memory Bandwidth

In theory, the GeForce 840M should be just a bit faster than the GeForce 830M overall. (explain)

GeForce 840M		16000 MB/sec
GeForce 830M		14400 MB/sec
	Difference: 1600 (11%)

Texel Rate

The GeForce 840M will be much (more or less 50%) faster with regards to anisotropic filtering than the GeForce 830M. (explain)

GeForce 840M		24696 Mtexels/sec
GeForce 830M		16464 Mtexels/sec
	Difference: 8232 (50%)

Pixel Rate

Both cards have exactly the same pixel fill rate, so theoretically they should be equally good at at AA, and be able to handle the same screen resolutions. (explain)

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 maximum amount of data (measured in MB per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better 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 are processed per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling 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 the video card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.