Radeon HD 3850 256MB vs Radeon HD 7990

Intro

Compare those specifications 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 works at a frequency of 1500 MHz on this specific model. It features 2048 SPUs along with 128 Texture Address Units and 32 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 7990		375 Watts
	Difference: 300 Watts (400%)

Memory Bandwidth

In theory, the Radeon HD 7990 should perform quite a bit faster than the Radeon HD 3850 256MB overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 523008 (987%)

Texel Rate

The Radeon HD 7990 will be quite a bit (about 2175%) faster with regards to anisotropic filtering than the Radeon HD 3850 256MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 232512 (2175%)

Pixel Rate

The Radeon HD 7990 is quite a bit (approximately 469%) faster with regards to full screen anti-aliasing than the Radeon HD 3850 256MB, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 50112 (469%)

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 largest amount of data (counted in MB per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range 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 calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.