Thanks Pleo. The temperature rise certainly frightened me and I won't be attempting Delete and Secure Erase again. I guess it could have been a false reading but I've used HDTune for quite a while and I've never seen temperatures do this before. Within a few minutes of aborting the program, the temperature had fallen by 5 to 10 degrees. Anyone like to confirm these temperature findings?

Pleo,

I’ve been using HD Tune for the last few months on a learning basis. It shows the same HD temperatures as does SpeedFan which is reassuring. The HD temperatures are certainly related to ambient temperature and are higher in the warmer times of the day. In the Dell 8400 that I was using, the primary HD temperature averaged mid 40’s (Celsius) and the secondary HD averaged 4 degrees lower. Doing processor intensive activities such as video editing and backup image creation, the temperature could reach the high 40’s (during the warmer times of the day). Manufacturers regard 55 degrees as a critical temperature, not to be exceeded.

I had read that wiping a disk caused the HD temperature to rise so that is why I opened HD Tune. I wasn’t expecting to see a rapid temperature rise to critical temperature over the space of a few minutes. As it was a linear rise I wasn’t prepared to continue so I can’t say whether it would have stopped at 55 degrees. I doubt it. I’d never seen a temperature change like this so I aborted the wipe.

Hard drive temperatures in my new Dell 9150 are at least 5 degrees lower than the 8400. The primary HD is now the cooler one. It’s related to case design. The 9150 has a BTX motherboard and a large fan next to the HDs.