Qualcomm Snapdragon 8cx Gen 2 5G vs Intel Core i7-7660U

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 i7-7660U

The Intel Core i7-7660U is a fast dual-core SoC for notebooks and Ultrabooks based on the Kaby Lake architecture and was announced in January 2017. The CPU has two processor cores clocked at 2.5-4 GHz (two cores up to 3.8 GHz). The processor can execute up to four threads simultaneously thanks to Hyper Threading. It is also equipped with an Intel Iris Plus Graphics 640 GPU with 64 MB eDRAm, a dual-channel memory controller (DDR4) as well as VP9 and H.265 video decoding as well as encoding. The chip is still manufactured in a 14nm process with FinFET transistors.

Compared to the Core i7-7600U, the 7660 does have a higher single-core Turbo of 4 GHz (+100 MHz), but a lower dual-core Turbo (-100 MHz) and a lower base frequency (-300 MHz). However, the CPU part can also use the 64 MB eDRAM as L5 cache.

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

At 2.5-4 GHz, the Core i7-7660U has a slightly lower frequency (except for the single-core Turbo) compared to the Core i7-7600U, but the CPU part can also use the 64 MB eDRAM, so the performance should be similar.

Graphics

The integrated Intel Iris Plus 640 Graphics is the GT3e model of the Kaby Lake GPU (Intel Gen. 9.5). It has 48 Execution Units running at 300-1050 MHz and the performance is comparable to a GeForce 920MX thanks to fast eDRAM cache. However, there aren't any significant improvements compared to the old Iris Pro 540, so modern games can often not be played smoothly or only at the lowest or medium settings, respectively.

Contrary to Skylake, Kaby lake now also supports H.265/HEVC Main 10 with a 10-bit color depth as well as Google's VP9 codec. The dual-core Kaby Lake processors 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 15 Watts, which is typical for ULV chips. Depending on the usage scenario, the TDP can vary between 7.5 (cTDP Down) and 25 Watts.