I checked the Asus web site again and Bios 211 appears to be the latest release.
I'm not really sure whether the BSODs started soon after the last Bios update was installed but it is likely.
Asus Support advised to jump into Bios and select optimised defaults, if that did not stop the BSOD then the G53 required repair via an Asus approved service agent.
Big problem is that I am never sure if this answer came off a flow chart of "maybe" solutions or derived from informed experience. Asus Support did not request the Windows 7 dump files to analyse.
I've adjusted the USB settings for the Balanced power management option, the USB suspend settings for plugin and battery are now set to false. USB on the G53 is mainly used for external drives used during backup.
I have noticed that the USB connectors on the G53 are noisy. If you move the connectors slightly when the disk drive is connected you can clearly see the drive power off. Move again and the power connection is restored. I was going to apply contact cleaner spray assuming gunk on the contacts. The problem seems to affect all four USB connectors spread 2 x 2 on either side of the chasis.
Verifier.exe is still running and targeting usbport.sys. Nothing indicated so far. Might discontinue.
Description BIOS 211
Firmware change File Size 1,2 (MBytes) 2011.03.28 update Download from
Description BIOS 210
Update USB3.0 File Size 1,2 (MBytes) 2010.12.31 update Download from
Description BIOS 209
First release File Size 1,2 (MBytes) 2010.10.27 update Download from