Radeon HD 4650 512MB vs Radeon HD 6950

Intro

Compare all of that to the Radeon HD 6950, which has GPU clock speed of 800 MHz, and 1024 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also is comprised of 1408 SPUs, 88 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 6950		200 Watts
	Difference: 145 Watts (264%)

Memory Bandwidth

Theoretically, the Radeon HD 6950 should be much faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 6950		160000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 144000 (900%)

Texel Rate

The Radeon HD 6950 will be a lot (about 267%) faster with regards to anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 6950		70400 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 51200 (267%)

Pixel Rate

The Radeon HD 6950 should be much (more or less 433%) faster with regards to anti-aliasing than the Radeon HD 4650 512MB, and should be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 6950		25600 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 20800 (433%)

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 (measured in MB per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

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