Radeon HD 4750 vs Radeon HD 6870

Intro

Compare those specs to the Radeon HD 6870, which comes with a core clock frequency of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It features 1120 SPUs, 56 TAUs, and 32 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 6870		151 Watts
	Difference: 76 Watts (101%)

Memory Bandwidth

The Radeon HD 6870, in theory, should perform much faster than the Radeon HD 4750 overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 83200 (163%)

Texel Rate

The Radeon HD 6870 will be a lot (about 116%) better at texture filtering than the Radeon HD 4750. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 27040 (116%)

Pixel Rate

The Radeon HD 6870 should be quite a bit (more or less 147%) faster with regards to AA than the Radeon HD 4750, and able to handle higher screen resolutions better. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 17120 (147%)

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 largest amount of data (measured in MB per second) that can be transferred past the external memory interface within a second. It's worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

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