Radeon HD 4750 vs Radeon HD 6750

Intro

Compare all that to the Radeon HD 6750, which comes with GPU clock speed of 725 MHz, and 512 MB of GDDR5 RAM running at 1000 MHz through a 128-bit bus. It also is comprised of 720 Stream Processors, 36 Texture Address Units, and 16 ROPs.

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

In theory, the Radeon HD 6750 is 25% quicker than the Radeon HD 4750 overall, due to its higher bandwidth. (explain)

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

Texel Rate

The Radeon HD 6750 is a small bit (approximately 12%) faster with regards to 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 will be a bit (about 1%) more effective at FSAA than the Radeon HD 6750, and will be able to handle 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: Memory bandwidth is the max amount of information (in units of MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 again. If it uses 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 high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total amount of 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka 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 - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.