if you mean an R9 280 then just use catalyst control center to find your max stable clocks, abck both sliders off one notch from that, write it doen, and then if you feel confident editing and flashing your card's bios you can use radeon bios editor to program those numbers which you wrote down into the card's bios so it runs those clocks at default. NOTE: Editing your card's BIOS is an advanced modification and should not be undertaken unless you are confident you know what you are doing. it is REALLY EASY to brick your card editiong the BIOS so this is not to be undertaken lightly.
Havent paid much attention to nvidia lately but if there really is an rtx2080 nvidia card, you can probably do the same with a modern version of rivatuner to find the clocks and nibitor to set them permanent (geforce 6800 era win ME apps but there should be a modern equivalent. like I said havent messed with nvidia in a looong time.)