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Difference between shutdown ( power off ) and restart ( reboot )

When I shutdown my Windows PC sometimes the boot time increases to 150% of the fastest boot it ever did. But when I reboot my PC, the boot is always as fast as possible.

What's the difference between a reboot and a 2-step reboot (shutdown, and the turn on again)?

Is there any way to force to do the slowest reboot mode?

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marked as duplicate by Tom Wijsman, Sathya, BinaryMisfit Oct 28 '10 at 21:25

This question was marked as an exact duplicate of an existing question.

99% of the time the difference is purely electrical and makes no difference to anything in the software one way or another.

Depending on your motherboard, the POST process on a warm reboot may be different - it may not do the same initializations on video and network cards, may not run the same memory tests, etc...this really varies from machine to machine but is probably the reason for a lot of the discrepancy that you're seeing in your particular machine. Without knowing specifically what it is I'd hesitate to conjecture as to what settings might achieve your goal - I'm sort of curious why you'd want to slow it down anyway?

It's also possible that your hard drive just spins up from a cold start REAAAAAAAAALLY slowly, but it would have to be damned slow to make that much of a difference in boot time. But it's certainly possible.

You might also see here and here for a little insight as to specifics.

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I think you are wrong. In Linux, there are different runlevels for a cold boot and a warm one. I am certain it's the same in Windows, since it behaves differently in each case. – Jader Dias Oct 28 '10 at 22:47
It doesn't matter on any platform. Everything is wiped from RAM under a reboot or shutdown. The only reason a reboot is "faster" is because like Shinrai said, the drives don't spin down and POST checks are abbreviated. – Force Flow Oct 28 '10 at 23:15
@Force Windows writes information about the last shutdown in the disk, and if it is a cold boot, sometimes it will check for new hardware devices that it wouldn't otherwise – Jader Dias Oct 29 '10 at 0:06
@Jader Do you have specifics on that? It would be news to me that the hardware enumeration process is different on a shutdown than a reboot under Windows but I'd really like to know :) – Shinrai Oct 29 '10 at 14:47

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