If you are viewing the temperature on the monitor(s), I'm not sure that is considered true "idle". What are you using to manage your displays? While not free, I have found nothing better than UltraMon
. My machines are very rarely "shut down" or turned off, they just go into Hybrid sleep mode. While rare, I occasionally have problems with my monitors going to sleep that is typically resolved with a reboot And that's been a problem ever since sleep mode was invented some time last century so not sure that would be a card problem, a Windows problem, or both.
If me, I might try with just one monitor attached. But if the voltages are not high, temps are under control, and there are no artifacts or other display problems, I would just leave it.