Ifixit

Source: iFixit.

This article was originally published on Sept. 26, 2015. It was updated on Jan. 14, 2016.

Apple (NASDAQ:AAPL) has been fortunate enough to enjoy continued iPhone growth each and every year since it launched its flagship smartphone in 2007. Last year's launch weekend saw a record 13 million in unit sales, a healthy jump compared to the 10 million units sold during the 2014 launch weekend. 

The Mac maker also occasionally switches suppliers for key components, which can make or break smaller companies that ride on Apple's coattails. Investors pay careful attention to iPhone teardowns each year to see if there are any changes.

iFixit often conducts the first of these teardowns. What did they find inside the iPhone 6s?

Previews first
The new taptic engine takes up some space below the battery, which meant Apple had to shift some things around to make space for the new part. There were significant changes to the display assembly in order to facilitate 3D Touch. The iPhone 6s display assembly is a notable 15 grams heavier than the iPhone 6, which more than accounts for the overall increase in total weight. The iPhone 6s is 14 grams heavier than the iPhone 6.

Battery capacity is modestly lower in the iPhone 6s, decreasing from 1810 mAh to 1715 mAh. Fortunately, there is no change in Apple's listed battery life specs, perhaps because the company was able to generate some power savings in a few areas (such as by integrating the M9 motion co-processor).

Apple also boosted the iPhone's RAM from 1 GB to 2 GB, which should improve overall performance and significantly strengthen the device's multitasking capabilities.

And now our feature presentation
Investors likely care most about which suppliers won or lost share on the iPhone's logic board. This is where fortunes are made and lost. Here are three of the more crucial ones.

In 2014, the iPhone 6 moved from one accelerometer to two accelerometers. There was a low-cost, low-energy one used for basic functions like screen rotation and a more powerful one with greater sensitivity for more demanding applications like games. InvenSense (NYSE:INVN) supplies the high-end solution with its integrated 6-axis gyroscope and accelerometer combo. Borsch kept the low-end accelerometer slot. It's a small consolation after InvenSense failed to win the Apple Watch like many investors had expected it to.

NXP Semiconductor (NASDAQ:NXPI) seems to have lost the motion co-processor spot, as expected. Prior-generation M-chips were rebranded versions of NXP ARM Cortex-M3 microcontrollers, but Apple has integrated the M9 directly into the A9 in the iPhone 6s. All is not lost, though, as it's also no surprise that NXP retained the NFC controller win with a newer version. iFixit also found an NXP display integrated circuit inside. You win some, you lose some.

Longtime cellular modem supplier Qualcomm (NASDAQ:QCOM) is still enjoying this slot, along with a handful of other less meaningful wins. The iPhone 6s includes a newer version of the LTE modem found in the iPhone 6. Take that, Chipzilla. Modems aren't the type of component that Apple would dual-source, either, since they're too vital and Qualcomm's modems are the best in breed.

Evan Niu, CFA owns shares of Apple. The Motley Fool owns shares of and recommends Apple, InvenSense, NXP Semiconductors, and Qualcomm. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.