Restarting the system with Windows 10 again.
Restarting the system with Windows 10 again.
It’s generally recommended to move the OS from your HDD to the new SSD. Your other drives don’t need a full format unless you’re replacing them entirely. Just reinstall everything as needed.
If any of the existing drives remain in your system and were previously used for booting, it's advisable. However, if you're interpreting your message correctly, transferring your HDD to an SSD isn't more advantageous than simply replacing it. A clean slate would be the better choice. Apart from that, you might need to guide certain programs on where to locate themselves again.
It could affect your system performance if you leave the drive connected. You’ll need to remove it before installing a new SSD. To locate it, check your device manager or system settings for the storage drive details.
Avoid direct actions unless you're careful during setup. Disconnecting drives you don't plan to reformat is wise in this case. With Steam, simply place the "old" folder as a directory. Other launchers might lack a "discover/find games" feature, so try installing the game and setting the install path to the "old" drive—this usually lets the launcher locate it.
Yes, 120GB is acceptable when you need only Windows and a few necessary applications or a single game.
If your budget allows, it's definitely worth considering. Bigger capacities offer some benefits too.