Radeon HD 4890 2GB vs Radeon HD 6870

Intro

The Radeon HD 4890 2GB has a GPU clock speed of 1000 MHz, and the 2048 MB of GDDR5 RAM is set to run at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Compare that to the Radeon HD 6870, which comes with a clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It is comprised of 1120 SPUs, 56 Texture Address Units, 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 4890 2GB 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 4890 2GB	Radeon HD 6870
Manufacturer	ATi	ATi
Year	Apr 2, 2009	October 2010
Code Name	RV790 XT	Barts XT
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16	PCIe x16
Memory	2048 MB	1024 MB
Core Speed	1000 MHz	900 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	975 MHz	1050 MHz
Unified Shaders	800(160x5)	1120
Texture Mapping Units	40	56
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	151 watts
Shader Model	4.1	5.0
Bandwidth	124800 MB/sec	134400 MB/sec
Texel Rate	40000 Mtexels/sec	50400 Mtexels/sec
Pixel Rate	16000 Mpixels/sec	28800 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel 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 maximum fill rate.