Radeon HD 4650 512MB vs Radeon HD 7950

Intro

Compare those specs to the Radeon HD 7950, which makes use of a 28 nm design. AMD has set the core speed at 800 MHz. The GDDR5 RAM runs at a speed of 1250 MHz on this particular model. It features 1792 SPUs as well as 112 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7950		200 Watts
	Difference: 145 Watts (264%)

Memory Bandwidth

In theory, the Radeon HD 7950 will be 1400% faster than the Radeon HD 4650 512MB in general, due to its greater data rate. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 224000 (1400%)

Texel Rate

The Radeon HD 7950 should be much (more or less 367%) faster with regards to anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 70400 (367%)

Pixel Rate

The Radeon HD 7950 should be much (approximately 433%) faster with regards to anti-aliasing than the Radeon HD 4650 512MB, and also able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7950		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 megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card 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 most pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated 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 drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.