I do believe Chromium still has to be patched to support HW decode via vaapi, while recent Firefoxen turn it on out of the box. So it's likely that Chromium is

I do believe Chromium still has to be patched to support HW decode via vaapi, while recent Firefoxen turn it on out of the box. So it's likely that Chromium is using software rendering, bypassing any driver-related bugs.