Radeon HD 4850 X2 512MB vs Radeon HD 4890 2GB

Intro

The Radeon HD 4850 X2 512MB comes with a GPU core speed of 625 MHz, and the 512 MB of GDDR3 memory runs at 993 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Compare those specifications to the Radeon HD 4890 2GB, which comes with a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, and 16 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 4850 X2 512MB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 4890 2GB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 4850 X2 512MB	Radeon HD 4890 2GB
Manufacturer	ATi	ATi
Year	Nov 7, 2008	Apr 2, 2009
Code Name	R700	RV790 XT
Fab Process	55 nm	55 nm
Bus	PCIe 2.0 x16 (PCIe bridge)	PCIe 2.0 x16
Memory	512 MB (x2)	2048 MB
Core Speed	625 MHz (x2)	1000 MHz
Shader Speed	N/A MHz (x2)	(N/A) MHz
Memory Speed	993 MHz (x2)	975 MHz
Unified Shaders	800(160x5) (x2)	800(160x5)
Texture Mapping Units	40 (x2)	40
Render Output Units	16 (x2)	16
Bus Type	GDDR3	GDDR5
Bus Width	256-bit (x2)	256-bit
DirectX Version	DirectX 10.1	DirectX 10.1
OpenGL Version	OpenGL 3.0	OpenGL 3.0
Power (Max TDP)	250 watts	190 watts
Shader Model	4.1	4.1
Bandwidth	127104 MB/sec	124800 MB/sec
Texel Rate	50000 Mtexels/sec	40000 Mtexels/sec
Pixel Rate	20000 Mpixels/sec	16000 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 amount of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.