Radeon HD 4650 1GB vs Radeon HD 6750 1GB

Intro

Compare those specs to the Radeon HD 6750 1GB, which comes with clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 720 SPUs as well as 36 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 6750 1GB		86 Watts
	Difference: 31 Watts (56%)

Memory Bandwidth

The Radeon HD 6750 1GB should theoretically perform quite a bit faster than the Radeon HD 4650 1GB overall. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 41600 (186%)

Texel Rate

The Radeon HD 6750 1GB should be a lot (approximately 36%) better at anisotropic filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 6900 (36%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6750 1GB is superior to the Radeon HD 4650 1GB, by far. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 6800 (142%)

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

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.