Radeon HD 4890 1GB vs Radeon HD 6970

Intro

Compare those specifications to the Radeon HD 6970, which comes with a clock speed of 880 MHz and a GDDR5 memory speed of 1375 MHz. It also features a 256-bit bus, and makes use of a 40 nm design. It is made up of 1536 SPUs, 96 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 6970		250 Watts
	Difference: 60 Watts (32%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6970 should in theory be much better than the Radeon HD 4890 1GB in general. (explain)

Radeon HD 6970		176000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 51200 (41%)

Texel Rate

The Radeon HD 6970 is a lot (more or less 111%) better at AF than the Radeon HD 4890 1GB. (explain)

Radeon HD 6970		84480 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 44480 (111%)

Pixel Rate

The Radeon HD 6970 will be quite a bit (about 76%) better at full screen anti-aliasing than the Radeon HD 4890 1GB, and also will be capable of handling higher resolutions more effectively. (explain)

Radeon HD 6970		28160 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 12160 (76%)

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 (in units of megabytes per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.