GeForce 820M vs GeForce GT 315

Intro

Compare those specifications to the GeForce GT 315, which has core clock speeds of 625 MHz on the GPU, and 790 MHz on the 512 MB of DDR3 memory. It features 48 SPUs as well as 16 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
GeForce GT 315		52 Watts
	Difference: 37 Watts (247%)

Memory Bandwidth

In theory, the GeForce GT 315 should perform quite a bit faster than the GeForce 820M in general. (explain)

GeForce GT 315		25280 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 9280 (58%)

Texel Rate

The GeForce 820M should be just a bit (approximately 15%) more effective at anisotropic filtering than the GeForce GT 315. (explain)

GeForce 820M		11504 Mtexels/sec
GeForce GT 315		10000 Mtexels/sec
	Difference: 1504 (15%)

Pixel Rate

The GeForce GT 315 should be much (about 74%) better at full screen anti-aliasing than the GeForce 820M, and should be capable of handling higher resolutions without slowing down too much. (explain)

GeForce GT 315		5000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 2124 (74%)

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 data (measured in megabytes per second) that can be transferred across the external memory interface in a second. It is calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.