Radeon HD 3870 X2 1GB vs Radeon HD 6870

Intro

The Radeon HD 3870 X2 1GB uses a 55 nm design. ATi has set the core frequency at 825 MHz. The GDDR4 memory works at a speed of 1126 MHz on this particular card. It features 320(64x5) SPUs along with 16 TAUs and 16 Rasterization Operator Units.

Compare those specifications to the Radeon HD 6870, which makes use of a 40 nm design. ATi has clocked the core speed at 900 MHz. The GDDR5 RAM works at a frequency of 1050 MHz on this particular card. It features 1120 SPUs along with 56 Texture Address Units and 32 Rasterization Operator Units.

Price Comparison

Please note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.

Radeon HD 3870 X2 1GB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 6870 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 3870 X2 1GB	Radeon HD 6870
Manufacturer	ATi	ATi
Year	Jan 28, 2008	October 2010
Code Name	R680	Barts XT
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16/(internal PCIe 1.1 x16)	PCIe x16
Memory	1024 MB (x2)	1024 MB
Core Speed	825 MHz (x2)	900 MHz
Shader Speed	N/A MHz (x2)	(N/A) MHz
Memory Speed	1126 MHz (x2)	1050 MHz
Unified Shaders	320(64x5) (x2)	1120
Texture Mapping Units	16 (x2)	56
Render Output Units	16 (x2)	32
Bus Type	GDDR4	GDDR5
Bus Width	256-bit (x2)	256-bit
DirectX Version	DirectX 10.1	DirectX 11
OpenGL Version	OpenGL 3.0	OpenGL 4.1
Power (Max TDP)	N/A watts	151 watts
Shader Model	4.1	5.0
Bandwidth	144128 MB/sec	134400 MB/sec
Texel Rate	26400 Mtexels/sec	50400 Mtexels/sec
Pixel Rate	26400 Mpixels/sec	28800 Mpixels/sec

Memory Bandwidth: 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. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 again. If 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 texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the video 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 chip can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.