Thanks Linkinworm/DieByZero, that’s good to know. My PC has a ******board with a 4gb max capacity (2004) so that means shopping for a new ******board/CPU/memory if I want to increase the memory. PC still runs latest games fine with 2 GTX670s though. And the mac is not upgradable unfortunately. 
edit: didn’t realise the alternative word for “mum” was a swearword!