Comment # 13 on bug 1155824 from robert spitzenpfeil

I'll add a comment of my own, as this issue, to me, sounds very similar to one
I have.

I observe mouse lag and GUI update lag (2-3 seconds) when copying large files
(20GB+) to and from my internal storage (SSD / NVME).

IOWAIT is about 30%, doesn't seem excessive to me.

Machine #1: CPU: i7-7700T, RAM: 16GB DDR4, storage: NVME (PCIE) + SSD (SATA)
Machine #2: CPU: i5-8265U, RAM: 8GB DDR4, storage: SSD (SATA)

I can run tests on the i7.