Radeon HD 3690/3830 vs Radeon HD 6850

Intro

Compare all of that to the Radeon HD 6850, which has a clock speed of 775 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 960 SPUs, 48 Texture Address Units, and 32 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 6850		127 Watts
	Difference: 52 Watts (69%)

Memory Bandwidth

The Radeon HD 6850, in theory, should be a lot faster than the Radeon HD 3690/3830 overall. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 101504 (383%)

Texel Rate

The Radeon HD 6850 is quite a bit (about 248%) more effective at texture filtering than the Radeon HD 3690/3830. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 26512 (248%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6850 is superior to the Radeon HD 3690/3830, and very much so. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 3690/3830		10688 Mpixels/sec
	Difference: 14112 (132%)

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 information (measured in MB per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type memory, the result should 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 AA, HDR and high resolutions.

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

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