Radeon HD 4650 512MB vs Radeon HD 6750

Intro

Compare that to the Radeon HD 6750, which comes with a core clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also makes use of a 128-bit memory bus, and uses a 40 nm design. It is made up of 720 SPUs, 36 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 6750		86 Watts
	Difference: 31 Watts (56%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6750 will be 300% faster than the Radeon HD 4650 512MB overall, because of its greater data rate. (explain)

Radeon HD 6750		64000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 48000 (300%)

Texel Rate

The Radeon HD 6750 should be a lot (more or less 36%) faster with regards to texture filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 6750		26100 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 6900 (36%)

Pixel Rate

The Radeon HD 6750 is a lot (more or less 142%) better at FSAA than the Radeon HD 4650 512MB, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 6750		11600 Mpixels/sec
Radeon HD 4650 512MB		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: Bandwidth is the max amount of information (counted in megabytes per second) that can be moved past the external memory interface in a second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour 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 rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.