Intel Core i7-8650U vs AMD A4-9120C

Intel Core i7-8650U

The Intel Core i7-8650U is a power efficient quad-core SoC for notebooks and Ultrabooks based on the Kaby Lake Refresh generation and was announced in August 2017. Contrary to its direct predecessor the Core i7-7600U, which were still dual-cores, the i7-8650U is equipped with four cores but at a lower base frequency of 1.9 GHz. The Turbo Boost can go up to 4,2 GHz and therefore also offer good short term single core speeds. The GPU is now named Intel UHD Graphics 620 but otherwise identical to the Intel HD Graphics 620. The integrated memory controller supports DDR4-2400 / LPDDR3-2133 and dual channel memory.

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

According to Intel, the new quad core models are up to 40% faster than their dual core predecessors. Due to the reduced TDP and the same 14nm+ process, the long term performance and throttling behaviour will be interesting and depending on the laptop design. Therefore, the older 35 Watt quad-core models should be faster in applications that demand longer CPU loads. The performance however is highly depending on the TDP settings and cooling solution of the laptop. Especially, longer loads will show varying results in different laptops.

Graphics

The integrated Intel UHD Graphics 620 (Intel Gen 9.5) is untouched from the 8th Gen Kaby Lake chips. With fast dual-channel memory it can reach the performance of a dedicated GeForce 920M.

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 (14nm+), the same as the 7th Gen Kaby Lake processors. 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.

AMD A4-9120C

The AMD A4-9120C is an entry-level chip from the Stoney-Ridge APU series for Chromebooks and entry level laptops (7th APU generation from 2016), which was announced early 2019. It is based on the similar named A4-9120 from 2016 but with a reduced TDP (6 versus 15 Watt) and reduced clock speeds of 1.6 - 2.4 GHz (compared to 2.2 - 2.5 GHz). Both CPUs integrate two CPU cores (one Excavator module with 2 integer and on FP unit).

It also includes a Radeon R4 GPU with 192 shaders at 600 MHz, as well as a single-channel DDR4-2133 memory controller, H.265 video engine and chipset with all I/O ports.

Architecture

Stoney Ridge is the successor of the Carrizo architecture and the design is almost identical. Thanks to optimized manufacturing processes and more aggressive Boost behavior, however, the clocks are a bit higher at the same power consumption. The memory controller now also supports DDR4-RAM, in this case up to 2133 MHz. Stoney Ridge is the designation for the smaller dual-core and single-core chip, while Bristol Ridge is the bigger quad-core chip with dual-channel memory controller. More technical details are available in the following articles:

• AMD's Bristol Ridge and Stoney Ridge Architecture
• AMD: Bristol Ridge APUs announced

Performance

Because of the significantly lower clock speed, the A4-9120C should be noticeably slower than the old A4-9120. AMD compares the A4-9120C with the Celeron N3350 in ChromeOS and sees a significant performance advantage for the A4. The efficiency however should be clearly worse as the A4-9120C is still manufactured in 28nm.

Power Consumption

AMD specifies the TDP of the A4-9120C with 6 Watts which should enable thin and light Chromebooks (even fanless).