IOS as a PPTP server limits?

I've configured VPDN for PPTP on a Cisco router before and it works
well as a Microsoft PPTP server, either for local authentication or to
a Radius server. It makes a decent replacement to a real NT server
for PPTP access in my limited trial.

However, I have not load tested it. With just a single user session,
I managed to make the CPU on a 1751 router go to 50% and on a 3725
router, it hit 16 ..
Telecom, Cabling and VoIP continues...
Tags: telecommunications telecom cabling Networking infrastructure