Arguably the most notable iPad technology is the chip that powers it, the new A4. The iPad's 1GHz system-on-a-chip, clocked at 1 GHz (compared to about 600MHz for the iPhone 3GS) was designed by Apple itself, through its acquisition of chipmaker PA Semiconductor. The processor's speed, along with the advanced power-management that allows Apple to brag that the iPad will be able to play 10 hours of continuous HD video without recharging, could be a significant selling point for the new device as it establishes its space in the marketplace.
The A4, as a system-on-a-chip (SoC), combines the CPU, graphics processor, memory management and other components such as the I/O controller on a single piece of silicon. Though Apple has not released detailed specs on the chip, observers have gathered details out of reports from suppliers, leaks and a healthy dose of conjecture.
Most observers are certain that the A4's CPU is ARM's Cortex-A9 MPCore, which is also used on the Qualcomm Snapdragon, a popular chipset used in smartphones and netbooks. The graphics processor is believed to be the ARM Mali 50 Series, and the entire ASIC was built by Samsung - whose process management is credited with the low power draw - based on designs by Apple, using its PA Semi brain trust. The result is an SoC that is substantially similar to the NVIDIA Tegra, with (at least claimed) better performance, especially relative to its power draw.
So when Apple CEO Steve Jobs described the A4 as "custom silicon that we designed for this product," he was certainly speaking the truth, though it may have left the impression that the entire chip was homegrown. Though it uses technology from other manufacturers, Apple's design of this SoC potentially gives it the edge over smartphone competitors, and its proprietary nature means Apple can keep it all for themselves. As Richard Doherty, director of technology consulting firm Envisioneering Group, told CNET this week, Apple has an edge over companies like Qualcomm, Freescale, and others that license ARM chips:
There's nothing that I can see from ARM licensees or Intel that could challenge the power-per-watt, the power-per-buck, the power-per-cubic-millimeter of size. Apple is going to have quite a performance, battery efficiency, and cost advantage over the competition.
image via Apple