Microsoft is advising Vista beta testers to burn their downloaded ISOs as slowly as 1X or 2X to avoid corrupted media. It says that its failure telemetry data is showing that three quarters of failed Vista installations are due to dodgy DVD-Rs. Of course, the really interesting thing here is not that Vista installations are failing due to recording problems, but that for the first time, we have some widescale data on the problem of lack of optical media reliability.