Consider yourself lucky. That's why it sucks, it's seemingly almost random when it works and when it doesn't. More monitors and higher Hz increase the risk of high idle clocks but even some people with triple screen setups have low idle clocks while others with two 60Hz monitors have high idle clocks. Connection types also have an effect, at least sometimes. I currently have 144Hz + 60Hz and idle clocks are in the 1200-1700MHz range (sometimes I use a third 60Hz monitor as well and then my clocks are completely stuck at ~1700MHz but it's summer/hot so trying to use less devices). With two screens If I drop the 144Hz to 120Hz, I get ~300MHz idle clocks.