Radeon HD 4850 1GB vs Radeon HD 7990

Intro

Compare that 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 particular 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 4850 1GB		110 Watts
Radeon HD 7990		375 Watts
	Difference: 265 Watts (241%)

Memory Bandwidth

In theory, the Radeon HD 7990 should perform quite a bit faster than the Radeon HD 4850 1GB in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 512448 (806%)

Texel Rate

The Radeon HD 7990 is much (more or less 873%) better at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 218200 (873%)

Pixel Rate

The Radeon HD 7990 should be much (more or less 508%) more effective at AA than the Radeon HD 4850 1GB, and also capable of handling higher resolutions better. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 50800 (508%)

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 max amount of data (in units of MB per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the 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 per second. This is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the graphics 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 most pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.