GeForce 820M vs Radeon R9 M390X

Intro

Compare those specifications to the Radeon R9 M390X, which comes with a clock speed of 723 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It is made up of 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon R9 M390X		125 Watts
	Difference: 110 Watts (733%)

Memory Bandwidth

Theoretically, the Radeon R9 M390X should be a lot faster than the GeForce 820M overall. (explain)

Radeon R9 M390X		160000 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 144000 (900%)

Texel Rate

The Radeon R9 M390X will be much (approximately 704%) more effective at AF than the GeForce 820M. (explain)

Radeon R9 M390X		92544 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 81040 (704%)

Pixel Rate

The Radeon R9 M390X will be quite a bit (more or less 704%) better at FSAA than the GeForce 820M, and capable of handling higher resolutions while still performing well. (explain)

Radeon R9 M390X		23136 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 20260 (704%)

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 max amount of data (in units of megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics 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 maximum number of pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel 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.