Radeon HD 4890 1GB vs Radeon HD 6850

Intro

Compare that to the Radeon HD 6850, which comes with a clock frequency of 775 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 256-bit memory bus, and uses a 40 nm design. It is made up of 960 SPUs, 48 Texture Address Units, 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 1GB		190 Watts
	Difference: 63 Watts (50%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6850 should theoretically be a bit superior to the Radeon HD 4890 1GB in general. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 3200 (3%)

Texel Rate

The Radeon HD 4890 1GB should be a bit (about 8%) faster with regards to AF than the Radeon HD 6850. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 6850		37200 Mtexels/sec
	Difference: 2800 (8%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6850 is superior to the Radeon HD 4890 1GB, and very much so. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4890 1GB		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: Bandwidth is the max amount of data (in units of MB per second) that can be moved past the external memory interface in a second. It is worked out by multiplying the interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.