GeForce 820M vs GeForce GTX 465

Intro

Compare those specs to the GeForce GTX 465, which comes with GPU clock speed of 607 MHz, and 1024 MB of GDDR5 memory set to run at 802 MHz through a 256-bit bus. It also features 352 Stream Processors, 44 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
GeForce GTX 465		200 Watts
	Difference: 185 Watts (1233%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 465 is 541% quicker than the GeForce 820M in general, due to its higher data rate. (explain)

GeForce GTX 465		102592 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 86592 (541%)

Texel Rate

The GeForce GTX 465 will be quite a bit (approximately 132%) better at anisotropic filtering than the GeForce 820M. (explain)

GeForce GTX 465		26708 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 15204 (132%)

Pixel Rate

The GeForce GTX 465 will be quite a bit (approximately 575%) better at AA than the GeForce 820M, and capable of handling higher screen resolutions more effectively. (explain)

GeForce GTX 465		19424 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 16548 (575%)

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 maximum amount of information (counted in megabytes per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 number of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.