Radeon HD 3870 X2 1GB vs Radeon HD 4890 2GB

Intro

The Radeon HD 3870 X2 1GB uses a 55 nm design. ATi has set the core speed at 825 MHz. The GDDR4 memory is set to run at a speed of 1126 MHz on this card. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 Rasterization Operator Units.

Compare those specs to the Radeon HD 4890 2GB, which comes with core clock speeds of 1000 MHz on the GPU, and 975 MHz on the 2048 MB of GDDR5 memory. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator 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 3870 X2 1GB 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 3870 X2 1GB	Radeon HD 4890 2GB
Manufacturer	ATi	ATi
Year	Jan 28, 2008	Apr 2, 2009
Code Name	R680	RV790 XT
Fab Process	55 nm	55 nm
Bus	PCIe 2.0 x16/(internal PCIe 1.1 x16)	PCIe 2.0 x16
Memory	1024 MB (x2)	2048 MB
Core Speed	825 MHz (x2)	1000 MHz
Shader Speed	N/A MHz (x2)	(N/A) MHz
Memory Speed	1126 MHz (x2)	975 MHz
Unified Shaders	320(64x5) (x2)	800(160x5)
Texture Mapping Units	16 (x2)	40
Render Output Units	16 (x2)	16
Bus Type	GDDR4	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)	N/A watts	190 watts
Shader Model	4.1	4.1
Bandwidth	144128 MB/sec	124800 MB/sec
Texel Rate	26400 Mtexels/sec	40000 Mtexels/sec
Pixel Rate	26400 Mpixels/sec	16000 Mpixels/sec

Memory Bandwidth: Bandwidth is the largest amount of data (measured in MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 are applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.