Radeon HD 3690/3830 vs Radeon HD 6790

Intro

Compare all that to the Radeon HD 6790, which features a GPU core clock speed of 840 MHz, and 1024 MB of GDDR5 memory set to run at 1050 MHz through a 256-bit bus. It also is made up of 800 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3690/3830		75 Watts
Radeon HD 6790		150 Watts
	Difference: 75 Watts (100%)

Memory Bandwidth

The Radeon HD 6790 should theoretically be much faster than the Radeon HD 3690/3830 in general. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 107904 (407%)

Texel Rate

The Radeon HD 6790 should be a lot (more or less 214%) faster with regards to anisotropic filtering than the Radeon HD 3690/3830. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 22912 (214%)

Pixel Rate

The Radeon HD 6790 should be much (about 26%) better at AA than the Radeon HD 3690/3830, and also able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 3690/3830		10688 Mpixels/sec
	Difference: 2752 (26%)

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 maximum amount of information (measured in megabytes per second) that can be moved past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, 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 worked out by multiplying the total texture units by the core speed of the chip. The better 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 maximum amount of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill 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 reach the maximum fill rate.