Linksys BEFVP41 V1 and V2 cannot handle multiple VPN tunnels properly

Sad but true.
The left side of the graph is from when there were 12 VPN tunnels on one BEFVP41.
The right side of the graph is when 6 of those tunnels were moved to a second BEFVP41.
Next week, both of those units are getting replaced with a Cisco ASA.

I am very surprised how much of a difference there is on the graph overall.
I expected there to be some difference but the overall change is dramatic.

It doesn't help that they haven't upgraded the firmware since 2003 on the V1 and 2005 on the V2, but I suspect the CPU is underpowered or VxWorks's scheduler is allowing some processes/pipes to starve.