Independent analysis has shown that Apple was not overstating the capabilities and power of their A7 microprocessor when they called it “desktop class.” The chip is used in Apple’s iPhone 5s, iPad Air, and iPad mini with Retina Display.
The A7 sports the same number of execution ports as Intel’s Ivy Bridge chips and a reorder buffer equal to that found in the Haswell architecture, according to Anand Shimpi of AnandTech. Shimpi arrived at his conclusions by studying the A7 itself as well as Apple code commitments to the LLVM compiler project.
Shimpi wrote that the A7 is close to the power of Intel’s big core chips. “At the launch of the iPhone 5s, Apple referred to the A7 as being “desktop class” – it turns out that wasn’t an exaggeration.”
The number of execution ports determines how many instructions a processor can handle concurrently. Apple’s A7 can handle six instructions per clock cycle, the same as Intel’s Ivy Bridge chips, which were used in previous generation Apple MacBook Pro models.
The A7 also contains a 192-instruction reorder buffer, matching Intel’s Haswell design. A larger reorder buffer allows a bigger pool of instructions to choose from when a processor is deciding how best to complete its tasks.
Shimpi notes that most of the A7’s processing power is untapped, due to concerns about battery life. He says current generation iOS devices will run out of RAM long before reaching the performance limits of the A7.