Radeon HD 3850 512MB vs Radeon HD 3870 512MB

Intro

Compare all of that to the Radeon HD 3870 512MB, which comes with GPU clock speed of 775 MHz, and 512 MB of GDDR3 RAM running at 900 MHz through a 256-bit bus. It also is made up of 320(64x5) Stream Processors, 16 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 31 Watts (41%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 512MB is 9% quicker than the Radeon HD 3850 512MB overall, because of its greater data rate. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 4608 (9%)

Texel Rate

The Radeon HD 3870 512MB is a bit (approximately 16%) better at AF than the Radeon HD 3850 512MB. (explain)

Radeon HD 3870 512MB		12400 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 1712 (16%)

Pixel Rate

The Radeon HD 3870 512MB should be a bit (approximately 16%) more effective at full screen anti-aliasing than the Radeon HD 3850 512MB, and also should be able to handle higher resolutions better. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 3850 512MB		10688 Mpixels/sec
	Difference: 1712 (16%)

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 transferred over the external memory interface in a second. It is calculated by multiplying the bus width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.