In a video introducing the iPhone X, Apple design chief Jony Ive speaks in his usual sonorous tones about features like polished stainless steel and new formulations of glass. Twice, he also calls out a feature of the $999 device that its owners will never see: the A11 “bionic” processor powering the phone.

The new chip’s prominence reflects Apple’s deepening investment in chip design. Last week the company also revealed it had built new custom chips or chip components for artificial intelligence, graphics, and video. And Apple highlighted two new chips in its refreshed smartwatch, suggesting they helped the company add a cellular connection to the device without hurting its battery life.

Computer and gadget makers have traditionally outsourced the work of designing and making the processors at the heart of their products. In the PC era, Apple followed this path as well: The processors in its Macintosh computers were initially built by Motorola, and later by Intel. In smartphones, however, industry watchers say Apple’s strategy of designing chips itself has given it a big advantage—and arguably made its mobile chips the best on the planet.

“I don’t think that’s in dispute,” says Avi Greengart, who tracks mobile devices and platforms at analyst firm GlobalData. Linley Gwennap, founder of semiconductor analysts the Linley Group, agrees. “From what we’ve heard about the A11, I would expect Apple to be pushing the technology beyond what’s already industry-leading in the iPhone 7,” he says.

Apple discloses limited technical information about its chips, but said that by one measure the A11 chip inside the iPhone 8 and iPhone X is 25 percent faster than its predecessor in the iPhone 7. The company declined to make anyone available to discuss the A11 chip.

Apple argues that designing chips in-house allows them to be more tightly integrated with its other hardware and software. Gwennap says that can help engineers balance the tradeoffs inherent in packing a complex computer into the palm of your hand. The new 3-D facial-recognition camera in the iPhone X, for example, consumes additional power and requires speedy data processing. Apple’s new “neural engine” component should help address both issues.

Apple’s rivals love to take inspiration from the iPhone, but they can’t easily copy its chip strategy.

Samsung, the world’s largest phone maker, designs mobile processors as well as phones, but the Korean company’s conglomerate structure keeps its phone and chip-making units somewhat separate. Samsung’s Exynos processors must be designed to serve other customers, too. In addition, the company doesn’t control Google’s Android operating system that powers its phones, so it can’t tightly integrate chip designs and software.

Similar limitations apply to Qualcomm, which according to Strategy Analytics supplies more smartphone processors than any other company. It has to serve customers with diverse handset designs, and can’t target even its top-of-the-line chips at only the most expensive devices. Customers for Qualcomm’s flagship Snapdragon 835 processor include Chinese phone makers Xiaomi, OnePlus, and ZTE, which typically sell phones for significantly less than an iPhone.

“It is somewhat unfair to compare Apple’s chip designs to those of Qualcomm, Intel, or AMD,” Ben Bajarin of Creative Strategies wrote in a note after Apple’s event last week. Rivals “don’t have the luxury to focus a design on just one device or platform.”

Designing chips is a high-stakes, expensive business, because errors in a chip’s design can’t easily be fixed. Apple contracts with chip fab owners such as TSMC to get its designs manufactured. To gain expertise in designing chips, Apple acquired PA Semi in 2008 for a reported $278 million, and Intrinsity in 2010 for a reported $121 million. But Apple’s huge scale and profitability---it sold 170 million iPhones in the first nine months of its fiscal year---help it absorb the costs.