The game is getting random stutters and brief freezes during race, and worse when playing on Wiimmfi online, causing to desync (lagging and messing up place positions at the end), even my PC is good to run games at 60FPS at increased reso by 1.5x or 2x. I use both Dev version of Dolphin and Ishiiruka. I tried tweaking some settings -- Ubershaders (Hybrid), increase CPU override, Async shader, Fast EFB Access, etc, still no luck. 
What are the best settings to stop the stutter?
My PC specs here
OS: Windows 10 Pro, 64-bit
Model: Microsoft Surface Book 2
CPU: Intel® Core i5-7300U @ 2.60GHz
GPU: Intel® HD Graphics 620
RAM: 8GB
SSD: 256GB - SAMSUNG MZFLW256HEHP-000MV

What are the best settings to stop the stutter?
My PC specs here
OS: Windows 10 Pro, 64-bit
Model: Microsoft Surface Book 2
CPU: Intel® Core i5-7300U @ 2.60GHz
GPU: Intel® HD Graphics 620
RAM: 8GB
SSD: 256GB - SAMSUNG MZFLW256HEHP-000MV