GeForce 820M vs Radeon HD 7990

Intro

Compare that to the Radeon HD 7990, which makes use of a 28 nm design. AMD has clocked the core frequency at 950 MHz. The GDDR5 RAM is set to run at a speed of 1500 MHz on this card. It features 2048 SPUs along with 128 TAUs and 32 ROPs.

Display Graphs

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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

Radeon HD 7990		15520 points
GeForce 820M		850 points
	Difference: 14670 (1726%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 820M		15 Watts
Radeon HD 7990		375 Watts
	Difference: 360 Watts (2400%)

Memory Bandwidth

The Radeon HD 7990 should theoretically perform quite a bit faster than the GeForce 820M overall. (explain)

Radeon HD 7990		576000 MB/sec
GeForce 820M		16000 MB/sec
	Difference: 560000 (3500%)

Texel Rate

The Radeon HD 7990 is quite a bit (about 2014%) faster with regards to AF than the GeForce 820M. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce 820M		11504 Mtexels/sec
	Difference: 231696 (2014%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 7990 is a better choice, by a large margin. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce 820M		2876 Mpixels/sec
	Difference: 57924 (2014%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If 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 higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.