Dell XPS 14 (L421X) 30-60 Second Freezes on Windows Starting Up - Possibly due to Micron SSD

I've had my Dell XPS since February 2013 and have been experiencing issues with 30-60 second freezes when the computer loads Windows 8.

I thought that this might have been a software issue so have completely reinstalled the OS from the factory version of Windows 8 to a fresh Windows 8 Enterprise image - I am still experiencing the same issues.

All drivers are installed and I have installed all of the latest firmware releases - paying particular attention to the new firmware for the installed 'Micron C400 RealSSD 2.5" 7mm 512GB' disk drive which I believe is the culprit here. The latest firmware for the SSD has improved the SSDs behaviour (it no longer randomly disappears from the BIOS after a restart for example) but the 30-60 second freezing is still apparent - if I am able to open Task Manager in time it shows the disk usage at 100% utilisation but doesn't give any clues as to what is causing it as it simply displays a generic system service.

All Dell hardware checks come back with a clean bill of health so I am looking for some ideas on how to identify what the issue is here.