Could this be a Fake CPU Periodic Surge Alarm?

[dpsguard]

Hello All, my setup is real simple. I have a simple NAT setup with no port forwarding, no VPN, IDS or anything that could be consuming CPU. I do have HA of two old Supermicro servers with quad core Xeon with 12GB RAM. I have one 2 port Intel 10Gig card in each plus 2 onboard 1Gig interfaces. And I have hardware offloading options all enabled for the capable NIC (and tested by disabling also). I also have a simple Captive Portal. This is all a lab setup. And I have the boxes on latest version.

With no traffic passing thru or with say 25Mbps traffic generated via a high def YouTube stream, on the GUI, I see periodic jumps in CPU of 30 to 50% for few seconds (not on a schedule). In terms of any Cron, I only have one to do a reboot every Sunday at 3AM.

To rule out any GUI related issues, I first opened a SSH session and ran "top -aSH" and CPU is averaging 1% and may be max 3%. I keep watching SSH console as well as GUI and when Gui shows like 32%or 48%, output of top does not show any increase in CPU. I even logged out of GUI and kept watching for like half hour output of top and I don't see any issues. I did apply some optimizations and overall in my lab testing I don't see any issues. I don't have a way to simulate some large number of devices generating some traffic.  Regular speedtests or iperf tests dont stress CPU as well.

Could this be some messed up input to GUI for it to wrongly interpret the CPU and accordingly show some triangles on the graph? I do see some users complain about high CPU either a while ago on older versions, which by now, have all those bugs ironed out, or some that might be related to Virtualization. I have plain hardware boxes.

Thanks