internationnal rules for shipping insurance is 23/kg ... so for a cpu you will receve maybe 5€ ... i always ship with a real insurance . it's more expensive but if you have problem you are covered
i run 4k on server 2012 with 3072 mo of ram i don't bench with overkil but without it work well
we have, with a friend, noticed that way too . see many screen more powerfull than other with only xmp or c17 . i don't know why