Radeon HD 3870 X2 1GB vs Radeon HD 6990

Intro

The Radeon HD 3870 X2 1GB features core speeds of 825 MHz on the GPU, and 1126 MHz on the 1024 MB of GDDR4 RAM. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 Rasterization Operator Units.

Compare those specifications to the Radeon HD 6990, which features GPU clock speed of 830 MHz, and 2048 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also is made up of 1536 SPUs, 96 TAUs, and 32 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 X2 1GB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 6990 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 3870 X2 1GB	Radeon HD 6990
Manufacturer	ATi	ATi
Year	Jan 28, 2008	March 2011
Code Name	R680	Antilles
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16/(internal PCIe 1.1 x16)	PCIe 2.1 x16
Memory	1024 MB (x2)	2048 MB (x2)
Core Speed	825 MHz (x2)	830 MHz (x2)
Shader Speed	N/A MHz (x2)	(N/A) MHz (x2)
Memory Speed	1126 MHz (x2)	1250 MHz (x2)
Unified Shaders	320(64x5) (x2)	1536 (x2)
Texture Mapping Units	16 (x2)	96 (x2)
Render Output Units	16 (x2)	32 (x2)
Bus Type	GDDR4	GDDR5
Bus Width	256-bit (x2)	256-bit (x2)
DirectX Version	DirectX 10.1	DirectX 11
OpenGL Version	OpenGL 3.0	OpenGL 4.1
Power (Max TDP)	N/A watts	375 watts
Shader Model	4.1	5.0
Bandwidth	144128 MB/sec	320000 MB/sec
Texel Rate	26400 Mtexels/sec	159360 Mtexels/sec
Pixel Rate	26400 Mpixels/sec	53120 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the largest amount of data (counted in MB per second) that can be transferred past the external memory interface within a second. It's calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core clock speed. 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 potential to reach the maximum fill rate.