Version: 49.0.2623.111
OS: Chrome

What steps will reproduce the problem?
(1) Insert an SD card
(2) Attempt to play a .mov file from it


What is the expected output?
Video plays

What do you see instead?
Video either doesn't play or is unwatchably janky. Often when this happens several extensions will crash at the same time.
Task manager doesn't show any process consuming abnormal resources.

This is a regression. User says it worked fine a week ago.

Issue seems to be with slow access of the SD card. Copying files is also very slow.

Things I tried:
Removing extensions.
Disabling cloud backup
Using a different SD card
Tried in 2 different panther chromeboxes, and a samus
Tried with 2 different accounts

Video will USUALLY play after being copied to internal storage, but not always. I've been unable to find a consistent repro.

I'll attach a sample video once I'm somewhere with decent bandwidth.