Radeon HD 4750 vs Radeon HD 7870

Intro

Compare those specifications to the Radeon HD 7870, which has GPU core speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also is made up of 1280 SPUs, 80 Texture Address Units, 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 7870		175 Watts
	Difference: 100 Watts (133%)

Memory Bandwidth

The Radeon HD 7870 should theoretically perform a lot faster than the Radeon HD 4750 overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 102400 (200%)

Texel Rate

The Radeon HD 7870 should be a lot (about 242%) better at texture filtering than the Radeon HD 4750. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 56640 (242%)

Pixel Rate

The Radeon HD 7870 will be quite a bit (more or less 174%) faster with regards to full screen anti-aliasing than the Radeon HD 4750, and able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 20320 (174%)

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 maximum amount of data (counted in megabytes per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the bus width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are 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 better this number, the better the card will be at 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 that the graphics chip can possibly record to the local memory per second - measured in millions of pixels per second. The number 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 filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.