HTC Announces Mid-Range One M8s With Octa-Core Snapdragon 615 SoC
Looks aside, these are several differences between the two devices. The One M8s features a Qualcomm Snapdragon 615 System-on-Chip (Soc) and 2GB of LPDDR3 memory powering the 5-inch Full HD 1080p display. Storage chores are handled by 16GB of built-in NAND flash memory and expandable via a microSD card slot.

Other tidbits include a 13-megapixel and depth sensing rear-facing cameras, 5-megapixel front-facing camera, 802.11ac Wi-Fi, Bluetooth 4.1, USB 2.0, GPS, NFC support, 4G LTE connectivity, 2,840 mAh battery, and Android 5.0 with HTC Sense.
The major difference between the M8s and M8 is the SoC -- the latter uses a faster Snapdragon 801 with four Krait cores clocked at 2.26GHz. There's also a 32GB option on the M8, whereas it appears the M8s will only be offered with 16GB of built-in storage.
Pricing for the M8s is said to be £379.99 (around $565) outright in the United Kingdom. No word on whether or not the M8s will be available stateside.