Radeon HD 4850 512MB vs Radeon HD 7950

Intro

Compare all of that to the Radeon HD 7950, which comes with GPU core speed of 800 MHz, and 1536 MB of GDDR5 RAM set to run at 1250 MHz through a 384-bit bus. It also is made up of 1792 Stream Processors, 112 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 4850 512MB		110 Watts
Radeon HD 7950		200 Watts
	Difference: 90 Watts (82%)

Memory Bandwidth

In theory, the Radeon HD 7950 is 278% faster than the Radeon HD 4850 512MB in general, due to its higher data rate. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 176448 (278%)

Texel Rate

The Radeon HD 7950 will be quite a bit (more or less 258%) more effective at AF than the Radeon HD 4850 512MB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 64600 (258%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7950 is the winner, by a large margin. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 15600 (156%)

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 largest amount of data (counted in megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units 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 output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.