Radeon HD 4750 vs Radeon HD 6750

Intro

Compare those specs to the Radeon HD 6750, which has a core clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It is made up 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 4750		75 Watts
Radeon HD 6750		86 Watts
	Difference: 11 Watts (15%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6750 should in theory be much better than the Radeon HD 4750 overall. (explain)

Radeon HD 6750		64000 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 12800 (25%)

Texel Rate

The Radeon HD 6750 should be a small bit (approximately 12%) better at texture filtering than the Radeon HD 4750. (explain)

Radeon HD 6750		26100 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 2740 (12%)

Pixel Rate

The Radeon HD 4750 is just a bit (about 1%) better at AA than the Radeon HD 6750, and capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 4750		11680 Mpixels/sec
Radeon HD 6750		11600 Mpixels/sec
	Difference: 80 (1%)

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 information (in units of MB per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 are processed in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

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