Radeon HD 3850 256MB vs Radeon HD 4850 512MB

Intro

The Radeon HD 3850 256MB comes with a clock frequency of 668 MHz and a GDDR3 memory speed of 828 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It features 320(64x5) SPUs, 16 Texture Address Units, and 16 ROPs.

Compare all of that to the Radeon HD 4850 512MB, which comes with GPU clock speed of 625 MHz, and 512 MB of GDDR3 RAM set to run at 993 MHz through a 256-bit bus. It also is comprised of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 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 3850 256MB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 4850 512MB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 3850 256MB	Radeon HD 4850 512MB
Manufacturer	ATi	ATi
Year	Nov 19, 2007	Jun 25, 2008
Code Name	RV670 PRO	RV770 PRO
Fab Process	55 nm	55 nm
Bus	PCIe 2.0 x16/AGP 8x	PCIe 2.0 x16
Memory	256 MB	512 MB
Core Speed	668 MHz	625 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	828 MHz	993 MHz
Unified Shaders	320(64x5)	800(160x5)
Texture Mapping Units	16	40
Render Output Units	16	16
Bus Type	GDDR3	GDDR3
Bus Width	256-bit	256-bit
DirectX Version	DirectX 10.1	DirectX 10.1
OpenGL Version	OpenGL 3.0	OpenGL 3.0
Power (Max TDP)	75 watts	110 watts
Shader Model	4.1	4.1
Bandwidth	52992 MB/sec	63552 MB/sec
Texel Rate	10688 Mtexels/sec	25000 Mtexels/sec
Pixel Rate	10688 Mpixels/sec	10000 Mpixels/sec

Memory Bandwidth: Bandwidth is the maximum amount of data (measured in megabytes per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one 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 video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output 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 maximum fill rate.