Radeon HD 4890 1GB vs Radeon HD 6850

Intro

The Radeon HD 4890 1GB makes use of a 55 nm design. ATi has set the core speed at 1000 MHz. The GDDR5 RAM is set to run at a speed of 975 MHz on this particular model. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.

Compare all that to the Radeon HD 6850, which features GPU core speed of 775 MHz, and 1024 MB of GDDR5 memory set to run at 1000 MHz through a 256-bit bus. It also is made up of 960 Stream Processors, 48 TAUs, 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 4890 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 4890 1GB	Radeon HD 6850
Manufacturer	ATi	ATi
Year	Apr 2, 2009	October 2010
Code Name	RV790 XT	Barts Pro
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16	PCIe x16
Memory	1024 MB	1024 MB
Core Speed	1000 MHz	775 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	975 MHz (3900 MHz effective)	1000 MHz (4000 MHz effective)
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)	190 watts	127 watts
Shader Model	4.1	5.0
Bandwidth	124800 MB/sec	128000 MB/sec
Texel Rate	40000 Mtexels/sec	37200 Mtexels/sec
Pixel Rate	16000 Mpixels/sec	24800 Mpixels/sec

Memory Bandwidth: Bandwidth is the max amount of data (measured in megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

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