Radeon HD 4750 vs Radeon HD 6870

Intro

Compare those specifications to the Radeon HD 6870, which has clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 1120 SPUs along with 56 TAUs and 32 Rasterization Operator 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

In theory, the Radeon HD 6870 should be a lot faster than the Radeon HD 4750 in general. (explain)

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

Texel Rate

The Radeon HD 6870 is much (more or less 116%) better at AF 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 will be quite a bit (approximately 147%) faster with regards to FSAA than the Radeon HD 4750, and also capable of handling higher screen resolutions more effectively. (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: Bandwidth is the largest amount of data (measured in megabytes per second) that can be moved over the external memory interface in one second. It's calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount 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 also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.