Hello, I have a similar problem. My monitor is a Lenovo LT3053p with 2560x1600 @60Hz and my RaspberryPi is v3. My config.txt is the following and the Monitor shows two black bars, left and right. hdmi_cvt=2560 1600 60 5 hdmi_drive=2 hdmi_group=2 hdmi_mode=87 hdmi_force_hotplug=1 config_hdmi_boost=4 ...