Radeon HD 4870 X2 vs Radeon HD 6870

Intro

The Radeon HD 4870 X2 has a clock speed of 750 MHz and a GDDR5 memory speed of 900 MHz. It also makes use of a 256-bit bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Compare those specifications to the Radeon HD 6870, which comes with a clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 1120 SPUs, 56 TAUs, and 32 Raster Operation 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 4870 X2 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 4870 X2	Radeon HD 6870
Manufacturer	ATi	ATi
Year	Aug 12, 2008	October 2010
Code Name	R700	Barts XT
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16 (PCIe bridge)	PCIe x16
Memory	1024 MB (x2)	1024 MB
Core Speed	750 MHz (x2)	900 MHz
Shader Speed	N/A MHz (x2)	(N/A) MHz
Memory Speed	900 MHz (x2)	1050 MHz
Unified Shaders	800(160x5) (x2)	1120
Texture Mapping Units	40 (x2)	56
Render Output Units	16 (x2)	32
Bus Type	GDDR5	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)	350 watts	151 watts
Shader Model	4.1	5.0
Bandwidth	230400 MB/sec	134400 MB/sec
Texel Rate	60000 Mtexels/sec	50400 Mtexels/sec
Pixel Rate	24000 Mpixels/sec	28800 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the max amount of information (measured in MB per second) that can be transported across the external memory interface in one second. It is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 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 texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.