Radeon HD 4890 2GB vs Radeon HD 6850

Intro

Compare those specifications to the Radeon HD 6850, which has core clock speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 960 SPUs as well as 48 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6850		127 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 63 Watts (50%)

Memory Bandwidth

The Radeon HD 6850, in theory, should be a bit faster than the Radeon HD 4890 2GB in general. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 3200 (3%)

Texel Rate

The Radeon HD 4890 2GB is a small bit (approximately 8%) faster with regards to AF than the Radeon HD 6850. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
Radeon HD 6850		37200 Mtexels/sec
	Difference: 2800 (8%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6850 is superior to the Radeon HD 4890 2GB, by far. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 8800 (55%)

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 maximum amount of data (in units of MB per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number of texture units of the card by the core 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 the graphics card can possibly write to its local memory in one 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 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 get to the max fill rate.