Radeon HD 6870 vs Radeon HD 7850

Intro

Compare all that to the Radeon HD 7850, which has GPU clock speed of 860 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also is made up of 1024 Stream Processors, 64 Texture Address Units, and 32 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
Radeon HD 6870		151 Watts
	Difference: 21 Watts (16%)

Memory Bandwidth

Performance-wise, the Radeon HD 7850 should theoretically be a small bit superior to the Radeon HD 6870 in general. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 6870		134400 MB/sec
	Difference: 19200 (14%)

Texel Rate

The Radeon HD 7850 should be a small bit (approximately 9%) more effective at texture filtering than the Radeon HD 6870. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 6870		50400 Mtexels/sec
	Difference: 4640 (9%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6870 is the winner, though not by far. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 7850		27520 Mpixels/sec
	Difference: 1280 (5%)

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 information (counted in MB per second) that can be moved across the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 are applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write 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 core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.