The difference is the warranty. While the boxed version has a 24-month warranty, the tray version has no warranty or only a 1-year warranty. The tray versions are actually not intended for the consumer market, but for the device manufacturers who install the CPUs in their PCs. I would advise against buying the tray version.

The CPUs themselves have no difference.
This one is the boxed version. So in a box, with CPU cooler, with paperwork, etc. The other one is a tray version, without box, without CPU cooler, without paperwork, etc.

Thanks for the help