The big picture: Thanks to optimized software and hardware, Apple is able to get away with outfitting the iPhone XS with a smaller battery compared to the iPhone X it replaces without compromising battery life (in fact, it lasts longer than last year's flagship).

Apple in a required filing with China's Ministry of Industry and Information Technology has revealed the amount of RAM and the battery capacity of each of its new iPhones - information the Cupertino-based company doesn't readily advertise.

According to listings on the regulatory agency's website, the iPhone XS and iPhone XS Max both feature 4GB of RAM while the more affordable iPhone XR packs 3GB of RAM.

As for battery capacity, the listings reveal that the iPhone XS has a 2,658mAh pack which is slightly smaller than the 2,716mAh battery found in the iPhone X. The newer iPhone XS boasts 30 more minutes of battery life according to Apple.

The larger iPhone XS Max, meanwhile, has a 3,174mAh battery. Apple said during last week's unveiling that this handset will last up to 90 minutes longer than the iPhone X. The iPhone XR is said to pack a 2,942mAh battery and according to Apple, boasts the most battery life of the three with up to 25 hours of talk time, 13 hours of Internet use and 16 hours of video playback thanks to its 6.1-inch LCD display operating at a lower resolution than the iPhone XS and iPhone XS Max.

Apple's new iPhone XS and iPhone XS Max launch on September 21 followed by the iPhone XR on October 26. Pricing starts at $999, $1,099 and $749, respectively.

Teardown image courtesy iFixit