Radeon HD 4650 1GB vs Radeon HD 6750

Intro

Compare those specifications to the Radeon HD 6750, which features a core clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 128-bit bus, and makes use of a 40 nm design. It is comprised of 720 SPUs, 36 TAUs, and 16 Raster Operation 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		86 Watts
	Difference: 31 Watts (56%)

Memory Bandwidth

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

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

Texel Rate

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

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

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 6750 is a better choice, and very much so. (explain)

Radeon HD 6750		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 max amount of information (counted in megabytes per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the card's 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 AA, High Dynamic Range and higher screen resolutions.

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

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