Be careful with this. Buying "tray" processors likely means any warranty you get is whatever is offered directly by the seller.even the i9 can b bought in "tray" mode , so pic what you like and we pick what we like .
I have bought them before. Nothing wrong with that route, as long as you go in "eyes open".
If the price difference is less than 5% or so, I will pay the extra money and get the retail-boxed version, just for the sake of better warranty and product support.