Radeon HD 4850 1GB vs Radeon HD 6850

Intro

Compare all of that to the Radeon HD 6850, which has core speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 960 SPUs along with 48 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 6850		127 Watts
	Difference: 17 Watts (15%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6850 should theoretically be much superior to the Radeon HD 4850 1GB in general. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 64448 (101%)

Texel Rate

The Radeon HD 6850 is quite a bit (about 49%) more effective at texture filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 12200 (49%)

Pixel Rate

The Radeon HD 6850 will be quite a bit (more or less 148%) faster with regards to anti-aliasing than the Radeon HD 4850 1GB, and also will be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 14800 (148%)

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 max amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. It's calculated by multiplying the interface width by the speed of its memory. If it uses DDR type RAM, it must 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, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.