Radeon HD 3650 256MB vs Radeon HD 6750 1GB

Intro

Compare those specifications to the Radeon HD 6750 1GB, which has a clock frequency of 725 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 128-bit bus, and uses a 40 nm design. It is comprised of 720 SPUs, 36 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3650 256MB		78 Watts
Radeon HD 6750 1GB		86 Watts
	Difference: 8 Watts (10%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6750 1GB should theoretically be much better than the Radeon HD 3650 256MB overall. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 3650 256MB		25600 MB/sec
	Difference: 38400 (150%)

Texel Rate

The Radeon HD 6750 1GB is quite a bit (about 350%) faster with regards to AF than the Radeon HD 3650 256MB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 3650 256MB		5800 Mtexels/sec
	Difference: 20300 (350%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6750 1GB is a better choice, by far. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 3650 256MB		2900 Mpixels/sec
	Difference: 8700 (300%)

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 largest amount of data (measured in MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total texture units of the card 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 applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.