Does memtet86 write any data to the hard drive? or leave any data in memory once the test is complete. If so does turning of the machine or reboot clears the memory?

I don't think you are going to get any "memtest" experts, however memtest from memory only tests memory (I.E. RAM) and will not apply any changes to the hard drives as it has no reason to touch them. Remember that hard drive disc space in computing is referred to as storage and not memory.

memtest doesn't even know what a hard drive is. All it does is run data into RAM and back again, once the machine is rebooted, it is like nothing even happened.

Hopefully a reboot will clear memory. There are many situations that it may not.

To be sure of a cold boot. Turn off machine, unplug ac and press power button a few times. That will normally ensure a true cold boot. Some machines either by design or by faulty parts or what ever may not fully return all gates and junctions to normal on a reboot.

Hi,

Excuse me?

Pressing a logic power on button will clear the supply how? If the PSU is of the old style then possible drain but we are speaking of switching supplies therefore residual in the switching caps would decay but over time.

As for memory state during power on, it would be static. Depending on POST if volatile test is done if not then the state would be random depending on the memory control refresh states.

If there was enough power left in the caps to power the mobo's power controll circuitry properly, it would attempt to power up and thus maybe drain the caps faster. At least, I think that's the idea. I doubt it would actually do anything. It's also somewhat pointless since they normally discharge inside 30 seconds anyway.

That is normally true, but there were a few odd mobos that kept memory powered across a soft reboot. I'm not sure why. They were never particularly common. It's still widely considered a best practice to leave your computer unplugged for a full minute if you need to clear the RAM.

Hi,

Doesn't work that way. The power on switch on a modern MB is a logic sense switch that will trigger the control circuitry. With the PSU plugged in there is a standby control voltage that supplies the circuit. Once you remove power via unplugging or a master power switch then that voltage is no longer available.

Soft reboot is different than a cold start with a POST. Soft boot was used to implement the control area of the memory so the recovery would be manageable or possible. To want or need to have cleared RAM is moot. What's the point of it? Your need of a zeroed RAM will gain what? Heck if need be then just run a volatile/destructive memory test before init of your OS. If one is thinking a virus or trojan is resident then you have a storage problem that would init such. That storage problem could be cmos or even hdd or the like then you should address that.