While parallel downloading is generally a massive upgrade, you might want to disable it if:
The website's server must support "byte-range requests" for this to work. opera://flags/#enable-parallel-downloading
The setting is an experimental feature in the Opera browser designed to increase download speeds . ⚡ What it does While parallel downloading is generally a massive upgrade,
Here’s a starting point for a or research note : opera://flags/#enable-parallel-downloading