Question about bandwidth usage

[Kryten]

Hey there,

I got a question from one of our customers which I cannot really answer yet and I hope to get some help here again 🙂

The customer is complaining about low throughput from the Clients to the Internet and while most of the problems seem to be related to a poorly optimized ThreadPrevention Policy and high utilization of the appliance in general (high CPU load and Mem usage), there is one thing we cannot explain yet:

When the customer is testing the throughput via HTTP/HTTPS downloads from the Internet he gets about 20-30 Mbit/s for a single connection, which is not really much. When he opens ten of those connections simultaneously, he gets 200-300 Mbit/s in total.

According to the customer the involved interfaces have been checked and they are not reaching any limit.

Now the Question:
Why is one conection not using as much throughput as it can?  There is no QoS used anywhere, so in my understanding a single connection should still use all available bandwith it can get. Is there a limit on how much throughput one deeply inspected connection can have in total?

Hoep to get some insight into this.

Cheers,

Alex