Radeon HD 3870 512MB vs Radeon HD 4850 1GB

Intro

The Radeon HD 3870 512MB has a GPU core speed of 775 MHz, and the 512 MB of GDDR3 memory is set to run at 900 MHz through a 256-bit bus. It also is comprised of 320(64x5) Stream Processors, 16 Texture Address Units, and 16 Raster Operation Units.

Compare that to the Radeon HD 4850 1GB, which comes with GPU clock speed of 625 MHz, and 1024 MB of GDDR4 RAM set to run at 993 MHz through a 256-bit bus. It also features 800(160x5) SPUs, 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 3870 512MB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 4850 1GB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 3870 512MB	Radeon HD 4850 1GB
Manufacturer	ATi	ATi
Year	Nov 19, 2007	Jun 25, 2008
Code Name	RV670 XT	RV770 PRO
Fab Process	55 nm	55 nm
Bus	PCIe 2.0 x16/AGP 8x	PCIe 2.0 x16
Memory	512 MB	1024 MB
Core Speed	775 MHz	625 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	900 MHz	993 MHz
Unified Shaders	320(64x5)	800(160x5)
Texture Mapping Units	16	40
Render Output Units	16	16
Bus Type	GDDR3	GDDR4
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)	106 watts	110 watts
Shader Model	4.1	4.1
Bandwidth	57600 MB/sec	63552 MB/sec
Texel Rate	12400 Mtexels/sec	25000 Mtexels/sec
Pixel Rate	12400 Mpixels/sec	10000 Mpixels/sec

Memory Bandwidth: Bandwidth is the maximum amount of data (measured in MB per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. If it uses DDR RAM, it must be multiplied by 2 once 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 AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs 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 is also dependant 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.