First off, 90°C under load for mid-high end cards (especially AIB) is pretty normal. I'd clock using afterburner for a perfect or a mild OC to push the threshold and save that profile for gaming alone.
70°C at idle is sketchy. Bad heat dissipation/thermals, dust in the fans, malfunctioning fans/wires not plugged in to the PCB (not spinning), graphic intensive BG workload (check task manager if something is running) among a plethora of reasons.
Some update, i have installed the GPU in my case and measured the temp, in celsius.
Here is when its idle
and under load
Temps look fine to me, but when its under load is extremely loud, like vacuum cleaner.
I was thinking to open it and change paste, but I have seen on internet that there some thermal pads on memory chips, and now I am afraid to open it and damage those thermal pads.
btw this is not MSI card, its Gigabyte 2070 super gaming OC version.
This is normal for your card. You're done here.
About the sound, can you differentiate between a coil whine and the one you're experiencing?
A coil whine is a screeching sound emitted from your GPU's coils which are there as inductors to pass stable/consistent power delivery, all the time, depending upon the task and workload, and when that coil vibrates.
Basically ALL GPU's have coil whine, we just don't hear them out loud because of N number of variables, like atmosphere sound, cases being open, load etc. The short term solution is to undervolt your GPU and cap the FPS either in-game or GPU software. 300+ FPS have the most intolerable coil whine.
What you're describing here maybe (don't quote me on this because YMMV) faulty GPU fans. A friend had this issue, changed them and it was fine. But she never had high temps like in your case. So, check all these variables here to narrow down.