GeForce 820M vs GeForce GTX 465

Intro

Compare all that to the GeForce GTX 465, which has a GPU core clock speed of 607 MHz, and 1024 MB of GDDR5 memory running at 802 MHz through a 256-bit bus. It also is comprised of 352 SPUs, 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 should be 541% faster than the GeForce 820M in general, because of its greater data rate. (explain)

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

Texel Rate

The GeForce GTX 465 is quite a bit (about 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

If using a high resolution is important to you, then the GeForce GTX 465 is the winner, and very much so. (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 largest amount of information (counted in MB per second) that can be transported over the external memory interface in a second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 processed per second. This figure is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.