Chrome: 67.0.3388.0 (Official Build) canary (64-bit) (cohort: Clang-64)
Chrome: 65.0.3325.181 (Official Build) (64-bit) (cohort: Stable)
Firefox: 52 ESR
JAWS: 2018
NVDA: 2018.1.1

Steps to repro:
# With JAWS running, Visit http://www.audiogames.net/
# Press 'c' to navigate to the combo box
# Press enter to enter forms mode
# Use arrow keys to navigate the options
# Note the time it takes JAWS to announce each focused option

Expected: Option focused should be verbalized nearly at the same time as pressing the arrow keys
NVDA: Works as expected
Firefox: Works as expected with JAWS and NVDA

Actual: JAWS takes 1-3 seconds to begin speaking