Radeon HD 3870 512MB vs Radeon HD 4850 2GB

Intro

Compare those specifications to the Radeon HD 4850 2GB, which uses a 55 nm design. AMD has set the core frequency at 625 MHz. The GDDR4 memory runs at a frequency of 993 MHz on this particular model. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 4 Watts (4%)

Memory Bandwidth

In theory, the Radeon HD 4850 2GB should perform a small bit faster than the Radeon HD 3870 512MB in general. (explain)

Radeon HD 4850 2GB		63552 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The Radeon HD 4850 2GB should be quite a bit (about 102%) more effective at texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 12600 (102%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 3870 512MB is the winner, and very much so. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 2400 (24%)

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 max amount of information (in units of megabytes per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at handling 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 card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.