It might work or give bsodsIf i upgrade from 3rd gen i3 to 12th gen system can i plug in the old HDD with windows 10 without any changes or format.
Not necessarily, it may or may not work.From googlin a bit i found that in windows 10 there are no issues with changing hardware.
will be fine. I dropped an SSD that was used in a desktop with 10th gen i3 into my laptop that runs on a Celeron and it booted fine. Same when I changed my desktop from Intel to AMD. clean install is recommended but not necessary.If i upgrade from 3rd gen i3 to 12th gen system can i plug in the old HDD with windows 10 without any changes or format.