When running headless (without monitor, keyboard, mouse attached) FreeBSD versions 8.2, 8.3, 9.0 and NetBSD version 5.0 has known issues (FreeBSD PR 156596, NetBSD 46596) to generate extremely high interrupt rates. The issue is also known as an interrupt storm and happens when PCI interrupts are shared. Often EHCI is on the same interrupt (#16, irq16) as VGAPCI. Other users reported to have success by attaching a PS/2 keyboard.
The Intel NUC DC3217BY BIOS has no option to disable the onboard video/GPU. We don't need VGA output (headless operation). We do need USB: the boot drive (SDHC card) is attached via a USB bridge.
How can FreeBSD configured to not hit the high interrupts rates, or limit the interrupt rate on ehci0? For example how to disable VGA irq assignment in FreeBSD?