Radeon HD 4650 1GB vs Radeon HD 7950 3GB

Intro

Compare that to the Radeon HD 7950 3GB, which makes use of a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory runs at a speed of 1250 MHz on this particular model. It features 1792 SPUs as well as 112 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 145 Watts (264%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 3GB is 971% quicker than the Radeon HD 4650 1GB overall, because of its higher bandwidth. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 217600 (971%)

Texel Rate

The Radeon HD 7950 3GB should be much (more or less 367%) faster with regards to anisotropic filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 70400 (367%)

Pixel Rate

The Radeon HD 7950 3GB should be quite a bit (more or less 433%) faster with regards to anti-aliasing than the Radeon HD 4650 1GB, and also will be able to handle higher resolutions better. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4650 1GB		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: Bandwidth is the max amount of data (in units of megabytes per second) that can be transported over the external memory interface within a second. The number is calculated by multiplying the interface width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

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