GeForce 820M vs Radeon R9 M275X

Intro

Compare those specs to the Radeon R9 M275X, which has a GPU core clock speed of 900 MHz, and 2048 MB of GDDR5 memory set to run at 1125 MHz through a 128-bit bus. It also is made up of 640 SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon R9 M275X		50 Watts
	Difference: 35 Watts (233%)

Memory Bandwidth

Theoretically speaking, the Radeon R9 M275X should be a lot faster than the GeForce 820M overall. (explain)

Radeon R9 M275X		72000 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 56000 (350%)

Texel Rate

The Radeon R9 M275X will be quite a bit (approximately 213%) better at AF than the GeForce 820M. (explain)

Radeon R9 M275X		36000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 24496 (213%)

Pixel Rate

The Radeon R9 M275X will be a lot (more or less 401%) better at FSAA than the GeForce 820M, and also capable of handling higher resolutions without losing too much performance. (explain)

Radeon R9 M275X		14400 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 11524 (401%)

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 transported past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour 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 output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.