Qualcomm Snapdragon 660 vs Qualcomm Snapdragon 615 MSM8939

Qualcomm Snapdragon 660

The Qualcomm Snapdragon 660 (SD660) is a fast mid-range ARM-based SoC largely found on Android tablets and smartphones. Announced in mid 2017, the SD660 is the successor to the Snapdragon 625. It features 8 Kryo 260 cores (custom design, 64-Bit capable) that are divided in two clusters. A fast cluster of four cores with up to 2.2 GHz and a power saving efficiency cluster with up to 1.8 GHz. Both clusters can also used together.

In addition to the 8 CPU cores, the SoC integrates a mid range Adreno 512 GPU with a LPDDR4 memory controller (dual-channel 1866 MHz)  and supports Wi-Fi (802.11ac + MIMO, max. 867 Mbps), Bluetooth 5, and LTE (X12 LTE modem with up to 600 Mbps download and 150 Mbps upload).

Performance

In Benchmarks of the Oppo R11, the CPU part of the Snapdragon SD660 performs between former high end Socs like the Snapdragon 821 in the Pixel XL and the Snapdragon 835. The graphics performance is however much lower, as the Adreno 512 is only a slight upgrade of the older Adreno 510 (due to the higher clock speed).

CPU

The Snapdragon 660 is based on a similar concept as ARM's big.LITTLE, which combines a low power CPU cluster (2x Kyro clocked at up to 1.8 GHz) and a performance CPU cluster (2x Kyro clocked at up to 2.2 GHz). The clock speed of each cluster can be individually adjusted (but not per core) and the lowest clock speed is 310 MHz (unverified).

Power Consumption

Thanks to the new 14 nm process, the energy efficiency has been improved noticeably compared to its 20 nm predecessors.

Qualcomm Snapdragon 615 MSM8939

The Qualcomm Snapdragon 615 MSM8939 is a mid-range ARMv8-based SoC largely for Android tablets and smartphones. Announced in February 2014, the S615 is one of the first 64-bit capable SoCs from Qualcomm. In addition to 8 Cortex-A53 CPU cores at up to 1.7 GHz, the SoC integrates an Adreno 405 GPU with a 2x 32-bit memory controller (LPDDR3-1600, 12.8 GB/s) and supports Wi-Fi (802.11ac), Bluetooth 4.0, UMTS, and LTE.

CPU

The Cortex-A53 is the successor to the very popular Cortex-A7 design. In addition to the new 64-bit capable ARMv8 ISA, the cores offer a variety of other improvements such as better branch prediction. This leads to a significantly higher performance per clock, which is even above the older Cortex-A9.

The eight cores of the Snapdragon 615 are divided into two quad-core clusters, each optimized for a different operating point. While one cluster can clock up to 1.7 GHz to handle more demanding applications, the other cluster is limited to a maximum of 1.0 GHz for energy-saving purposes. All eight cores can be active at the same time, although most applications aren't parallelized to support 8 cores efficiently.

Overall, the Snapdragon 615 offers a performance similar to that of the older Snapdragon 600 (Krait architecture).

GPU

Another new feature is the integrated graphics unit named Adreno 405 (550 MHz). The Adreno 400 series has been substantially redesigned and supports DirectX 11.2 (FL 11_1) including hardware tessellation, OpenGL ES 3.1, and OpenCL 1.2. Furthermore, the performance has been significantly improved, which is now similar to the Adreno 320 and PowerVR G6200.

Features

The Snapdragon 615 offers numerous wireless technologies such as Bluetooth 4.0 and WLAN 802.11a/b/g/n/ac as well as a Multi-SIM cellular modem supporting LTE cat. 4 (up to 150 Mbps), WCDMA, CDMA, EV-DO, TD-SCDMA and GSM/EDGE.

The SoC can encode and decode 1080p videos using dedicated hardware and stream content to displays with up to 2560 x 2048 pixels. A large number of video codecs including H.265 (playback only) will be supported. The camera ISP can handle sensors with up to 21 MP.

Power Consumption

The Snapdragon 615 is manufactured by TSMC in a 28 nm LP process. According to the specifications, we expect a medium or medium-high power consumption for use in medium-sized or larger smartphones and tablets.