Qualcomm Snapdragon 8cx Gen 2 5G vs Intel Core i7-7820HQ

Qualcomm Snapdragon 8cx Gen 2 5G

The Qualcomm Snapdragon 8cx Gen 2 5G Compute Platform (or SD8cx Gen2, SC8180XP) is a ARM based SoC for Windows laptops. It integrates a similar CPU part as the Snapdragon 855 (same cores but without the Prime Core feature) and is manufactured in 7nm at Samsung. The 4 Kryo 495 Gold cores are based on the ARM Cortex-A76 architecture (for performance) and clocked at 3.15 GHz under load. The 4 Kryo 495 Silver cores are small ARM Cortex-A55 cores for power efficiency and clocked at 1.8 GHz under load (most likely).

Compared to the predecessor, the Snapdragon 8cx, the Gen 2 offers higher clock speeds and an integrated 5G modem (X55 with Sub-6 GHz and mmWave support). Wi-Fi was also bumped up to Wi-Fi 6

The processor performance should be similar to a Intel Core i5 8th gen U-series (e.g. i5-8250U) according to Qualcomm. However, this is only the case for native ARM64 compiled Windows apps which are not that many (in mid 2019). 32 bit applications and games for AMD/Intel run in a rather slow emulation and 64 bit apps wont start at all (but an emulator should come in Windows in 2021).

The integrated Adreno 680 graphics card could also be a bit higher clocked.

The chip is very power efficient as its produced at TSMC in the modern 7 process. Therefore, laptops using the Snapdragon 8cx can be passively cooled (no fan) and should not throttle under constant load.

Intel Core i7-7820HQ

The Intel Core i7-7820HQ is a fast quad-core processor for notebooks based on the Kaby Lake architecture and was announced in January 2017. It is the second fastest model of the consumer series at the time of the announcement. Only the i7-7920HQ and Xeon E3-1535M v6 are faster. Besides four cores including Hyper-Threading support running at 2.9 - 3.9 GHz (4 cores up to 3.5 GHz, 2 cores up to 3.7 GHz), the processor is also equipped with the HD Graphics 630 GPU as well as a dual-channel memory controller (DDR3L-1600/DDR4-2400). It is manufactured in a 14nm process with FinFET transistors.

Architecture

Intel basically uses the same micro architecture compared to Skylake, so the per-MHz performance does not differ. The manufacturer only reworked the Speed Shift technology for faster dynamic adjustments of voltages and clocks, and the improved 14nm process allows much higher frequencies combined with better efficiency than before.

Performance

Due to the higher clock speeds, the performance of the i7-7820HQ is slightly faster than the old Skylake top model Core i7-6920HQ (2.9 - 3.8 GHz). The performance is sufficient even for very demanding tasks and on par with powerful desktop quad-core processors.

Graphics

The integrated Intel HD Graphics 630 has 24 Execution Units (similar to previous HD Graphics 530) running at 350 - 1100 MHz. The performance depends a lot on the memory configuration; it should be comparable to a dedicated Nvidia GeForce 920M in combination with fast DDR4-2133 dual-channel memory.

Contrary to Skylake, Kaby Lake now supports hardware decoding for H.265/HEVC Main 10 with a 10-bit color depth as well as Google's VP9 codec. The dual-core Kaby Lake processors, which were announced in January, should also support HDCP 2.2.

Power Consumption

The chip is manufactured in an improved 14nm process with FinFET transistors, which improves the efficiency even further. Intel still specifies the TDP with 45 Watts, but it can also be reduced to 35 Watts by the notebook manufacturers (cTDP down). This will obviously affect the performance, because the Turbo Boost cannot be maintained for longer periods.