Soltution is quite simple when you know where to look.
First, Benq's support told me that this behavior was part of the monitor's firmware and couldn't be disabled. They even suggested I buy a different monitor cause it was obvious this one didn't meet my requirement!!! (!)
To fix this issue, go into video setting and set it up so the graphic card takes care of the scaling instead of letting the display do the job. This way, you monitor is always feeded with the same resolution and the graphic card (nvidia in my case) is taking care of sclaing the images. You may even set it up so it stretch the image full screen or keep the ratio (you may end up with black borders thought).
Special thanks to {--M--}.
First, Benq's support told me that this behavior was part of the monitor's firmware and couldn't be disabled. They even suggested I buy a different monitor cause it was obvious this one didn't meet my requirement!!! (!)
To fix this issue, go into video setting and set it up so the graphic card takes care of the scaling instead of letting the display do the job. This way, you monitor is always feeded with the same resolution and the graphic card (nvidia in my case) is taking care of sclaing the images. You may even set it up so it stretch the image full screen or keep the ratio (you may end up with black borders thought).
Special thanks to {--M--}.