Radeon HD 3870 1GB vs Radeon HD 5750 512MB

Intro

Compare those specifications to the Radeon HD 5750 512MB, which comes with a core clock speed of 700 MHz and a GDDR5 memory frequency of 1150 MHz. It also uses a 128-bit memory bus, and uses a 40 nm design. It features 720(144x5) SPUs, 36 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5750 512MB		86 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 20 Watts (23%)

Memory Bandwidth

In theory, the Radeon HD 5750 512MB will be 2% quicker than the Radeon HD 3870 1GB overall, because of its higher bandwidth. (explain)

Radeon HD 5750 512MB		73600 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 1600 (2%)

Texel Rate

The Radeon HD 5750 512MB should be much (about 103%) faster with regards to AF than the Radeon HD 3870 1GB. (explain)

Radeon HD 5750 512MB		25200 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 12800 (103%)

Pixel Rate

The Radeon HD 3870 1GB will be a little bit (more or less 11%) faster with regards to full screen anti-aliasing than the Radeon HD 5750 512MB, and will be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 5750 512MB		11200 Mpixels/sec
	Difference: 1200 (11%)

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 maximum amount of data (counted 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 its memory clock speed. In the case of DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better 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 processed per second. This is worked out by multiplying the total number 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 in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its 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 core speed of the card. 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 of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.