GeForce 820M vs GeForce 840M

Intro

Compare that to the GeForce 840M, which features core clock speeds of 1029 MHz on the GPU, and 1000 MHz on the 2048 MB of DDR3 RAM. It features 384 SPUs as well as 24 TAUs and 8 ROPs.

Display Graphs

Hide Graphs

Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

GeForce 840M		1600 points
GeForce 820M		850 points
	Difference: 750 (88%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
GeForce 840M		30 Watts
	Difference: 15 Watts (100%)

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

The GeForce 840M is much (more or less 115%) more effective at texture filtering than the GeForce 820M. (explain)

GeForce 840M		24696 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 13192 (115%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce 840M is superior to the GeForce 820M, by a large margin. (explain)

GeForce 840M		8232 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 5356 (186%)

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 (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is worked out by multiplying the total amount of texture units of the card by the core 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 processed per second.

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