Qualcomm Snapdragon 660 vs Qualcomm Snapdragon 678

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 678

The Qualcomm Snapdragon 678 (SD678) is a mid-range ARM-based SoC largely found on Android tablets and smartphones. It features 8 Kryo 460 called cores (64-Bit capable) that are divided in two clusters. A fast cluster of two cores with up to 2.2 GHz and  based on the ARM Cortex-A76 design. And a power saving efficiency cluster with up to 1.7 GHz and based on much smaller ARM Cortex-A55 cores. Both clusters can also used together. Compared to the old Snapdragon 675, the clock speed of the cores was increased by 200 MHz for the A76 and 100 MHz for the A55 cores.

In addition to the 8 CPU cores, the SoC integrates a lower mid range Adreno 612 GPU, a X12 LTE Modem with up to 600 Mbps download (Cat 12) and 150 Mbps upload (Cat 13), a 802.11ac (Wifi 5) Wave 2 WLAN modem (up to 867 Mbps), a Bluetooth 5.0 radio, satellite positioning (GPS, QZSS, GLONASS, SBAS, Beidou and Galileo) and a video engine (up to 4k30 encoding and support for H.265, H.264, VP8 and VP9).

Performance

Compared to the old Snapdragon 675, the 678 is only slightly faster in our benchmarks. Thanks to the two fast Cortex-A76 based cores, the SD678 is able to even best the old high end Snapdragon 835 SoC in some benchmarks.

The Snapdragon 678 is produced in the same 11nm LPP (Low Power Plus) process at Samsung as the 675 which is a combination of 14nm and 10nm. Compared to 14nm LPP, the 11nm LPP process should be able to increase performance by 15% and decrease the chip size by 10% according to Samsung.