Radeon HD 4870 512MB vs Radeon HD 6850

Intro

The Radeon HD 4870 512MB uses a 55 nm design. ATi has set the core frequency at 750 MHz. The GDDR5 memory is set to run at a speed of 900 MHz on this particular card. It features 800(160x5) SPUs as well as 40 TAUs and 16 ROPs.

Compare those specifications to the Radeon HD 6850, which has core clock speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 960 SPUs along with 48 Texture Address Units and 32 ROPs.

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 512MB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 6850 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 4870 512MB	Radeon HD 6850
Manufacturer	ATi	ATi
Year	Jun 25, 2008	October 2010
Code Name	RV770 XT	Barts Pro
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16	PCIe x16
Memory	512 MB	1024 MB
Core Speed	750 MHz	775 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	900 MHz	1000 MHz
Unified Shaders	800(160x5)	960
Texture Mapping Units	40	48
Render Output Units	16	32
Bus Type	GDDR5	GDDR5
Bus Width	256-bit	256-bit
DirectX Version	DirectX 10.1	DirectX 11
OpenGL Version	OpenGL 3.0	OpenGL 4.1
Power (Max TDP)	150 watts	127 watts
Shader Model	4.1	5.0
Bandwidth	115200 MB/sec	128000 MB/sec
Texel Rate	30000 Mtexels/sec	37200 Mtexels/sec
Pixel Rate	12000 Mpixels/sec	24800 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the maximum amount of data (measured in MB per second) that can be transported past the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at 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 the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.