GeForce 820M vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which comes with GPU clock speed of 950 MHz, and 3072 MB of GDDR5 RAM running at 1500 MHz through a 384-bit bus. It also is made up of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

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

Performance-wise, the Radeon HD 7990 should in theory be quite a bit better 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 will be much (about 2014%) better at texture filtering than the GeForce 820M. (explain)

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

Pixel Rate

The Radeon HD 7990 will be a lot (about 2014%) better at AA than the GeForce 820M, and also will be able to handle higher resolutions more effectively. (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: Bandwidth is the largest amount of data (in units of MB per second) that can be moved across the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

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