Radeon HD 4870 1GB vs Radeon HD 6850

Intro

The Radeon HD 4870 1GB uses a 55 nm design. ATi has clocked the core frequency at 750 MHz. The GDDR5 memory runs at a frequency of 900 MHz on this particular model. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Compare those specifications to the Radeon HD 6850, which comes with GPU core speed of 775 MHz, and 1024 MB of GDDR5 RAM running at 1000 MHz through a 256-bit bus. It also is comprised of 960 SPUs, 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 1GB 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 1GB	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	1024 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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR type RAM, it 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.