ISP v.s. VPN line speeds

Unless you use split-tunneling, when your user is connected via VPN, he is limited by the speeds available to YOUR network - that is, the network where the VPN terminates. How big is the Internet pipe at your office?
Do you have any throttling or bandwidth usage limitations in effect for your VPN solution?

Of course it is possible.
The simplest case is:
The same user can have on other side of VPN tunnel also 100/10Mbps link, so effective transfer between two VPN locations would be 10/10Mbps. Download speed on one side - is limited by upload speed of other side of VPN tunnel. There's protocol overhead, decryption and encryption of traffic, it all takes time, so speed is always slower then unencrypted line (9.65Mbps - 7,94Mbps), etc...

As Predrag Iovic says... the VPN is limited by the *lower* of the upload speed at one end and corresponding download speed at the other end.  Then you apply this rule in both directions.

Perhaps less well known is that latency can have a major effect on apparent speed if the latency is large - such as half-way around the world.  In that case, latency affects hand-shaking speed which, in turn, affects actual throughput.  There are products being offered to help in those cases.

@rharland2009 - the office pipe is 100M
We do not have split tunnel so the VPN users are using our network pipe.

@Predrac jovic/fmarshall - Can you give me an example of this "the VPN is limited by the *lower* of the upload speed at one end and corresponding download speed at the other end.  Then you apply this rule in both directions."

Great thank you for the details!