Radeon HD 4870 512MB vs Radeon HD 6750

Intro

Compare those specifications to the Radeon HD 6750, which uses a 40 nm design. AMD has clocked the core speed at 725 MHz. The GDDR5 RAM runs at a frequency of 1000 MHz on this specific model. It features 720 SPUs as well as 36 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750		86 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 64 Watts (74%)

Memory Bandwidth

The Radeon HD 4870 512MB, in theory, should be quite a bit faster than the Radeon HD 6750 overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 51200 (80%)

Texel Rate

The Radeon HD 4870 512MB will be just a bit (about 15%) more effective at anisotropic filtering than the Radeon HD 6750. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
Radeon HD 6750		26100 Mtexels/sec
	Difference: 3900 (15%)

Pixel Rate

The Radeon HD 4870 512MB will be just a bit (more or less 3%) faster with regards to full screen anti-aliasing than the Radeon HD 6750, and also should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 4870 512MB		12000 Mpixels/sec
Radeon HD 6750		11600 Mpixels/sec
	Difference: 400 (3%)

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 (measured in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.