If the Quick Scan Report is reporting that you have Slow IO on your Log File, this can be an indication that transactions are taking a long time to complete.
If you are watching your wait stats, if you log file has slow IO, you will likely be seeing write log waits accumulating on transactions, for explicit transactions you will see these on the COMMIT statement.
Your transaction cannot complete until the transaction log has been written to disk. A slow transaction log file slows down every single write to your database.
Can you move your transaction logs to faster storage?