GeForce 825M vs GeForce GTX 870M

Intro

Compare all of that to the GeForce GTX 870M, which has GPU core speed of 941 MHz, and 3072 MB of GDDR5 RAM running at 1000 MHz through a 192-bit bus. It also is comprised of 1344 SPUs, 112 Texture Address Units, and 24 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 825M		33 Watts
GeForce GTX 870M		110 Watts
	Difference: 77 Watts (233%)

Memory Bandwidth

In theory, the GeForce GTX 870M should perform much faster than the GeForce 825M in general. (explain)

GeForce GTX 870M		96000 MB/sec
GeForce 825M		14400 MB/sec
	Difference: 81600 (567%)

Texel Rate

The GeForce GTX 870M is a lot (about 675%) faster with regards to anisotropic filtering than the GeForce 825M. (explain)

GeForce GTX 870M		105392 Mtexels/sec
GeForce 825M		13600 Mtexels/sec
	Difference: 91792 (675%)

Pixel Rate

The GeForce GTX 870M will be much (more or less 232%) more effective at FSAA than the GeForce 825M, and able to handle higher screen resolutions more effectively. (explain)

GeForce GTX 870M		22584 Mpixels/sec
GeForce 825M		6800 Mpixels/sec
	Difference: 15784 (232%)

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 max amount of data (counted in megabytes per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 again. If 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 number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.