Its just unbelievable the way this isssue isn't addressed. Does it mean I stop
using the routerboard and gove the edgemax router a try.
In an industry where time is money, it was more expensive for us to follow this through with Mikrotik support, than it was to replace all the mips-be devices with PPC ones. So we did, we replaced all the RB7xx's we had this issue on with RB1200's and they are fine.
For us it appeared to be triggered by SNMP on these devices, the flash and management processes would spike up and consume the CPU. We also noticed that it only happened on devices where high throughput/PPS were going through the bridge/routing stages, on devices that were just forwarding packets with MPLS we have never had an issue, however on devices doing L3 routing, or bridging a VPLS tunnel to a interface the issue would always occur.