Our Leading edge firewall is Sonicwall 2040 pro VPN Firewall appliance. We have a server in the DMZ from which we occasionally need to copy files to/from the LAN. When the copy job starts, the CPU jumps to 100% and all DMZ activity grinds to a halt until the the copy job completes. This happens even for small files. Copying those same files to other servers in the DMZ has no negative effects.
In watching the Sonicwall's process monitor, I can see that the" tNetTask" process is at 100% when the CPU is maxed out. Our zone settings are already set to Auto negotiate link speed.