From 20 secs to 70 is quite a jump - are you using a SSD as I've never heard of Win 7 booting that quick with a HDD.
I usually get 5 consecutive Error Disk 11 when I plug a certain external HDD in to create a system image, but as far as I know, it doesn't corrupt the saved image.
Download the trial version of HDSentinel, remembering to uninstall it when done as it has a 30 day clock.
While it will give a written report on the status of any connected disks, see what the S.M.A.R.T. reports for it.
On another laptop, a chkdsk and other 3rd party programs gave an internal HDD a clean bill of health, but HDSentinel was sounding the death knell for it so I decided to replace it rather than take a chance.
https://www.hdsentinel.com/hard_disk_sentinel_trial.phpHit the Download link in the left pane and select Save.
You can extract the .zip in your Downloads folder and then run the application.
Having uninstalled it when done, you can continue to load it from there as and when you want to check.