Large Time Machine Backup and Airport Extreme Bottleneck

Network Configuration:

Wall-Cable Modem (no wireless)-Airport Extreme-D-Link Switch (to extend the ports)-Devices

Three devices are plugged into the Airport Extreme. A wired connection directly from this computer, the D-Link Switch, and another remote wired connection.

In the switch I have plugged in, among other things, a Drobo5N NAS with 16TB worth of disk storage (netting 11 roughly usable space).

I am a photographer who has been at it awhile (10 years plus), so I have a large cache of picture files stored in RAW format.

On my local MacPro I have a pair of 1.5TB disks installed internally in a RAID 0 array for nearly 3TB of storage. I use most of it. The MacPro otherwise is unremarkable. I reconfigured it with an SSD boot disk and it has the original HDD drive along with an extra to fill out the remaining bay. My overall storage requirements for backup are 3.05TB.

I started the TimeMachine backup over the network and the performance seems slow. It ran some numbers out of the console and it looks like it's copying an average of about 5GB an hour on average.

I tried to do a quick review of the router settings but when I called up the Airport Utility it takes an extremely long time to show information. Since I started this thread, the message "Reading settings on (my) Airport Extreme" has been up, then finally as I was typing this line the information came through. It seems the router may be a bottleneck, but I am not sure.

The backup has been running 4 days and is about halfway done.

So where to go from here? Is this kind of performance in Time Machine the norm? Is the Airport causing this problem? If so, do I need to check for some sort of software upgrade or missing configuration? Not sure where to go next, but I am pretty sure I can move more than 5GB per hour over my network.

Any help appreciated.