Drive Wiper Runs Painfully Slowly -- Seems to Pause Frequently

CCleaner for Windows CCleaner Windows Bug Reporting
1

I am using Drive Wiper for the first time to clean up free space on the C drive of a desktop computer that has a large amount of free space (The C drive is 910 GB, and about 860 GB are free). I started the process yesterday and got about 25% of the way through after a couple of hours. I then left the house for a few hours, and when I came back, the process still sat at 25% complete. My guess is that the computer automatically went into sleep mode after a period of time and that halted the process.

Unfortunately another user inadvertently closed CCleaner shortly afterwards, so I had to start the process again last night. I've been running the process for more than 12 hours and the process is only 8% complete. The estimate is that another 4 1/2+ days are required to complete wiping the drive.

1) Should it really take this long?

2) Do I need to change settings on my computer so that

  • the screen never times out (it seems that CCleaner may be pausing even after screen timeouts)?
  • the computer never goes into sleep mode?
2

Yes wiping 860 Gb (especially if using multiple passes) will take forever. Wiping freespace will only benefit you if you are trying to sell the harddrive, it will bestow no performance boost and (if run often or with excessive wipes) lower the drive's life.