Radeon HD 4870 512MB vs Radeon HD 6950 2GB

Intro

Compare those specifications to the Radeon HD 6950 2GB, which comes with core speeds of 800 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1408 SPUs as well as 88 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 6950 2GB		200 Watts
	Difference: 50 Watts (33%)

Memory Bandwidth

In theory, the Radeon HD 6950 2GB should be 39% quicker than the Radeon HD 4870 512MB overall, because of its greater bandwidth. (explain)

Radeon HD 6950 2GB		160000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 44800 (39%)

Texel Rate

The Radeon HD 6950 2GB should be a lot (approximately 135%) better at anisotropic filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 6950 2GB		70400 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 40400 (135%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6950 2GB is a better choice, and very much so. (explain)

Radeon HD 6950 2GB		25600 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 13600 (113%)

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 largest amount of data (counted in MB per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can 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 - sometimes also referred to as 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.