Radeon HD 3850 1GB vs Radeon HD 7990

Intro

Compare that to the Radeon HD 7990, which has GPU core speed of 950 MHz, and 3072 MB of GDDR5 RAM set to run at 1500 MHz through a 384-bit bus. It also is comprised of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 1GB		75 Watts
Radeon HD 7990		375 Watts
	Difference: 300 Watts (400%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7990 should be quite a bit faster than the Radeon HD 3850 1GB overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 3850 1GB		52992 MB/sec
	Difference: 523008 (987%)

Texel Rate

The Radeon HD 7990 will be much (approximately 2175%) better at anisotropic filtering than the Radeon HD 3850 1GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 3850 1GB		10688 Mtexels/sec
	Difference: 232512 (2175%)

Pixel Rate

The Radeon HD 7990 will be much (approximately 469%) better at FSAA than the Radeon HD 3850 1GB, and also will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 3850 1GB		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: Bandwidth is the largest amount of information (counted in MB per second) that can be transferred across the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.