Radeon HD 4890 1GB vs Radeon HD 6950

Intro

Compare those specs to the Radeon HD 6950, which comes with GPU core speed of 800 MHz, and 1024 MB of GDDR5 RAM running at 1250 MHz through a 256-bit bus. It also features 1408 SPUs, 88 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 6950		200 Watts
	Difference: 10 Watts (5%)

Memory Bandwidth

The Radeon HD 6950 should theoretically perform much faster than the Radeon HD 4890 1GB overall. (explain)

Radeon HD 6950		160000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 35200 (28%)

Texel Rate

The Radeon HD 6950 will be much (more or less 76%) faster with regards to texture filtering than the Radeon HD 4890 1GB. (explain)

Radeon HD 6950		70400 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 30400 (76%)

Pixel Rate

The Radeon HD 6950 will be a lot (approximately 60%) more effective at full screen anti-aliasing than the Radeon HD 4890 1GB, and should be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 6950		25600 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 9600 (60%)

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 maximum amount of information (measured in megabytes per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.