GeForce 820M vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which has GPU clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 975 MHz through a 256-bit bus. It also is made up of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 175 Watts (1167%)

Memory Bandwidth

In theory, the Radeon HD 4890 1GB should be 680% faster than the GeForce 820M in general, because of its higher bandwidth. (explain)

Radeon HD 4890 1GB		124800 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 108800 (680%)

Texel Rate

The Radeon HD 4890 1GB is a lot (about 248%) better at texture filtering than the GeForce 820M. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 28496 (248%)

Pixel Rate

The Radeon HD 4890 1GB should be a lot (about 456%) faster with regards to full screen anti-aliasing than the GeForce 820M, and also should be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 13124 (456%)

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 largest amount of data (in units of MB per second) that can be transported across the external memory interface in one second. The number is worked out by multiplying the interface width by the speed of its memory. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.