I expected higher transfer speeds with multiple clients, but something seems to be holding performance back. As you can tell by taking a look at the screenshots below, the SoC isn't utilized fully, which is probably the reason for these transfer speeds.
With several clients connected and asking for lots of data at the same time, CPU utilization is high, which may cause issues if simultaneously running another demanding application (e.g., media transcoding). Performance is not that high, especially with six clients. However, RAM utilization is low.