|
It does sound likely that the adapter would be the issue.
There are multiple HDMI standards that support different resolutions. If your cable (or adapter) is only supporting an earlier version of the standard, it won't be able to use resolutions that were released later on. It's very disappointing that you often cannot find out what versions are supported so need to pay premium to get something that is likelier to support the latest...
As you've confirmed that your monitors both support the resolution and the 3070 is a modern card that will definitely also support that, it's more likely to be down to drivers (which you've upgraded so probably ruled out), cables or the adapter.
Let us know how you go.
|