Up to 1 in 190 machines crash over an 8 month period due to hardware failure
After the first crash, likelihood of the same crash re-occurring increases by up to two orders of magnitude
Recurrent failure will happens in 97 per cent of machines within 10 days of the first failure
15 to 39 per cent of machines exhibited intermittent faults.
The recommendation from the team involved? Build a more fault tolerant operating system.
For the full stats, we'd recommend reading the paper on Microsoft Research's page.