iPad 2 Teardown Reveals Bigger and Faster A5 Processor

Submitted by lalit on March 17, 2011 - 6:22pm.

Many websites have posted images and details about iPad 2 internals after teardown of the new Apple device. While most websites have just opened the new iPad and showed the internal components, some website have gone a step further and put the iPad’s heart the A5 processor under microscope and even x-rayed it.  This process not only revealed who manufactured the Apple designed processor, but also type of RAM, manufacturing process and detailed design of the new processor.

The first thing to note about A5 processor is that it’s almost double in size when compared to the last years A4 processor. The A5 processor die measures 12.1 x 10.1 mm, whereas the A4 die was only 7.3 x 7.3 mm. To find out complete design details of the new processor UBM TechInsights used optical die and SEM cross-section images to analyze important features such as die edge seal, metal 1 pitch, logic and SRAM transistor gate measurements. They found that even though both A4 and A5 are made using Samsung’s 45nm manufacturing process the difference in size is mainly because of the new CPU and GPU cores.

The old A4 processor used a single core Cortex-A8 CPU and a single core PowerVR SGX 535 GPU, whereas the new A5 processor comes with dual core Cortex A9 CPU and dual Core PowerVR SGX 543MP2 GPU. Also Chipworks found out that the new A5 processor has two 4.5Mb of cache memory for each core, in place of one 5.4Mb of cache memory in A4 processor. The above-mentioned changes along with some new on-chip features have increased the size of A5 processor, but have also increased CPU performance by 2X and GPU performance by 9X without increasing the power requirements by much.

One other factor contributing to increased performance in A5 chip is 512MB of RAM. Not only the A5 chip has doubled the amount of RAM from 256MB in A4 to 512MB, but it is also using faster Low Power DDR2 (LPDDR2) memory in place of LPDDR on A4 chip. According to Techinsights, Apple is using LPDDR2 memory made from Samsung and Elpida indicating, “Apple is fully prepared to package multiple LPDDR2 offerings.”

Many blogs have questioned Apple’s claim that A5 processor runs at 1GHz, point out benchmarking results that show 890-910 MHz clock speed for the CPU. However, the teardown of the A5 processor shows that the new CPU cores support dynamic clock speed switching depending on applications that is running and battery power that is available.

Apple is using advanced power management circuitry to control CPU and GPU clock speeds resulting in faster and better performance with increased battery life. For regular use the A5 processor can dynamically change CPU clock speed in range of 600MHz to 1GHz demanding on processing power requirements.

Overall, Apple has not just simply added more cores to their processors, but they have fine-tuned the processor to get maximum performance while increasing battery life.