Radeon HD 3850 1GB vs Radeon HD 4850 512MB

Intro

The Radeon HD 3850 1GB makes use of a 55 nm design. ATi has clocked the core frequency at 668 MHz. The GDDR3 RAM runs at a frequency of 828 MHz on this specific card. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 Rasterization Operator Units.

Compare all that to the Radeon HD 4850 512MB, which has a clock speed of 625 MHz and a GDDR3 memory speed of 993 MHz. It also makes use of a 256-bit bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, 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 1GB 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 1GB	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	1024 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 information (counted in megabytes per second) that can be moved across the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs 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 output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.