Yes, high router CPU usage can lead to packet loss if it causes the device to drop packets or slow down processing.
Yes, high router CPU usage can lead to packet loss if it causes the device to drop packets or slow down processing.
It's possible at any pace. When the router can't send packets as quickly as they arrive, its buffer fills and packets start dropping. If this happens without the router being involved, the issue is likely with the router itself. You might test downloading at full speed with and without the router to spot packet loss in one scenario but not another.