You really need to reformat, you’ll spend more time getting the new hardware to work properly with the old install than what it would just take to install it all over again. It won’t ask you for verification but getting rid of old drivers/settings takes a bit of mucking around. I tried to change a CPU on my parents first home built pc without reformatting it and it was BSOD after BSOD until I reformatted it.
A good 920 will hit 4.2GHz with anything but insane voltages, you might surprise yourself if you are lucky enough to pick a cherry.
Good choice on the air cooler, top unit.