Can I simply reverse 2 hard drives?

[DeeLee]

Fixing older desktop with 2 hard drives. The primary drive is literally too small and the secondary drive is generous. Can I just unplug them and reverse them? Both work fine. Thanks

 

[DSzymborski]

No, the hard drives hold the data, so switching them just changes the ports. If you want to switch the data, you'll have to do that manually and then specify the new primary drive with the operating system install as the boot device.

 

[DeeLee]

No, the hard drives hold the data, so switching them just changes the ports. If you want to switch the data, you'll have to do that manually and then specify the new primary drive with the operating system install as the boot device.

Sorry my bad, I should have said can I physically unplug them and reverse them to make the larger one the primary boot. Yes, I am planning a complete install but I'd prefer the larger drive to put Windows10 on it this time.

 

[stdragon]

Assuming you installed an OS to the larger one, then all need to do is change the boot drive priority in BIOS. If you haven't installed an OS yet, it might actually be easier to unplug the smaller one, then install Windows 10 to the large. Then change boot priority after reconnecting the smaller drive. That way, you don't have to make any modifications to the smaller drive in terms of loss of data.

 

[Dugimodo]

The boot order can be changed in the BIOS, but yes physically swapping them should also change the boot order if you want to do it that way.
You can use any drive connected to any of the SATA ports as your primary boot drive so there's not actually any need to physically swap them.

I suggest though if you are reinstalling widows temporarily disconnect the smaller drive and only have the large drive connected. This is because the windows installer likes to hide some files on a secondary drive when detected and can cause boot issues later, and also it makes sure you install windows exactly where you want it.

Steps:
Disconnect the smaller drive
Install windows on the larger drive
Re connect the small drive
Go into the BIOS and set the boot order to boot from the large drive first
Boot into windows and confirm everything is working
Retrieve any files you want from the smaller drive then wipe it (deleting the partitions and create a new single one is the easiest way IMO) Unless you want to keep it as a backup boot device of course.

 

[USAFRet]

No, the hard drives hold the data, so switching them just changes the ports. If you want to switch the data, you'll have to do that manually and then specify the new primary drive with the operating system install as the boot device.

Sorry my bad, I should have said can I physically unplug them and reverse them to make the larger one the primary boot. Yes, I am planning a complete install but I'd prefer the larger drive to put Windows10 on it this time.

If you're going to do a full reinstall, it mostly does not matter which port they're plugged into.
You need to disconnect all other drives, and do a clean install on whichever one you want.
How to do a CLEAN installation of Windows 10