Just to update you all. Everything has been going fine since the upgrade to 1gbps. We started getting alternative style attacks of lots of TCP SYN requests which clogged the CPU on the router. What I ended up doing is taking the target outside of the firewall and directly attached to the border router (since firewalling takes up a lot of CPU). All has been good since with about 1 attack greater than 300mbps doing nothing.
I am happy now :)