Radeon HD 4870 2GB vs Radeon HD 7750

Intro

Compare those specifications to the Radeon HD 7750, which features a clock frequency of 800 MHz and a GDDR5 memory frequency of 1125 MHz. It also uses a 128-bit bus, and uses a 28 nm design. It is made up of 512 SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7750		55 Watts
Radeon HD 4870 2GB		150 Watts
	Difference: 95 Watts (173%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 2GB should theoretically be a lot superior to the Radeon HD 7750 overall. (explain)

Radeon HD 4870 2GB		115200 MB/sec
Radeon HD 7750		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 4870 2GB will be a small bit (more or less 17%) faster with regards to AF than the Radeon HD 7750. (explain)

Radeon HD 4870 2GB		30000 Mtexels/sec
Radeon HD 7750		25600 Mtexels/sec
	Difference: 4400 (17%)

Pixel Rate

The Radeon HD 7750 is a small bit (about 7%) more effective at AA than the Radeon HD 4870 2GB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7750		12800 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 800 (7%)

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 (in units of 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 its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.