Radeon HD 4850 2GB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which has clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1024 SPUs as well as 64 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 2GB		110 Watts
Radeon HD 7850		130 Watts
	Difference: 20 Watts (18%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7850 is 142% quicker than the Radeon HD 4850 2GB in general, due to its higher data rate. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 7850 is much (about 120%) better at anisotropic filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 30040 (120%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7850 is a better choice, by far. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 17520 (175%)

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: Memory bandwidth is the max amount of information (counted in megabytes per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the interface width by the speed of its memory. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 number of texture map elements (texels) that are processed per second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, 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 most pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's 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 is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.