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Llano – the Graphics Section

Llano graphics has been lifted from the Radeon graphics and borrows heavily from the Redwood GPU cores in the Radeon HD 5500 and 5600.

The Llano connects to the external DDR3 memory using the integrated North Bridge inside the Llano. The integrated graphics in Llano has to share the memory bus with the processor. This arrangement is slightly disadvantageous when compared to the discrete graphics that have their own dedicate memory. The integrated Graphics in Llano, however, has a priority over the CPU in accessing the memory.   Sandy bridge on the other hand profits by having a shared L3 Cache (it shares L3 between CPU and GPU), which improves the things a bit.

The Llano GPU section can have maximum five SIMD engines. Each engines comprises of 80 Radeon Cores. So you get a max total of 400 Radeon Cores. AMD reduces the number of the SIMD engines enabled depending upon whether it is a high end part ( A8 Series on highest end) or low end part ( A4 Series on the lowest end). Each SIMD engine has 4 texture unit. So you can get 20 Texture units on high end APUs.

Llano APU Series Number of SIMD engines Number of Radeon Cores Number of Texture Units
A8 5 400 20
A6 4 320 16
A4 3 240 12

 

These specifications match up to the Radeon HD 5570 and 5670 cards. AMD names the integrated graphics inside the Llano with HD 6xxx – a marketing ploy to confuse common users ? We do not know that – but for the moment keep in mind that the Llano APUs are basically the similar to the Radeon HD 5570 and HD 5670.

The Llano does upgrade the UDV engine to UDV3 and there is not a great degree of difference between the HD 5000 and the HD 6000 series. Trinity should improve upon the things.

The memory controller had to be redesigned in the Llano, as, it communicates with  the North Bridge in place of the dedicated DDR3/GDDR5 memory.  The memory becomes slower but there is some advantage when CPU shares the memory with GPU. The data no more needs to be moved from the main memory to the GPU memory. The GPU can simply point to the data that CPU points to.

 Dual Graphics

What if you have an additional discrete graphics in the system, i.e., one in addition to the integrated discrete graphics ?  AMD has made some intelligent design choice here. If you have dual graphics, both of them collaborate to give you the sum of the performance of the two graphics.

This gives a lot of flexibility and choices. For example, if the notebook is running on battery, it may shut down the discrete graphics completely to save power.

The dual graphics working together does not work with DirectX 9 or below. The Application will need to have DirectX 10 or DirectX 11 to be able to take the advantage of the dual graphics.


Related posts:

  1. Llano – The CPU section
  2. Intel HD Graphics 3000
  3. AMD Llano Architecture – the Fusion APU
  4. AMD Radeon HD 6520G vs Intel HD Graphics 3000
  5. Intel HD Graphics 3000 vs Radeon HD 6480G

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