Radeon HD 3850 256MB vs Radeon HD 6790

Intro

Compare those specifications to the Radeon HD 6790, which comes with core speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 6790		150 Watts
	Difference: 75 Watts (100%)

Memory Bandwidth

Performance-wise, the Radeon HD 6790 should in theory be quite a bit better than the Radeon HD 3850 256MB in general. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 81408 (154%)

Texel Rate

The Radeon HD 6790 should be quite a bit (approximately 214%) better at AF than the Radeon HD 3850 256MB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 22912 (214%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 6790 is the winner, and very much so. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 3850 256MB		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 max amount of data (in units of megabytes per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

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