Radeon HD 4650 512MB vs Radeon HD 6950

Intro

Compare all that to the Radeon HD 6950, which features a clock frequency of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit memory bus, and uses a 40 nm design. It is made up 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 speaking, the Radeon HD 6950 should perform much faster than the Radeon HD 4650 512MB in general. (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 much (approximately 267%) more effective at AF 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 (approximately 433%) better at FSAA than the Radeon HD 4650 512MB, and should be capable of handling higher screen 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 (in units of MB per second) that can be transported past the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

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