Recently I've purchased new ASUS ENGTX560 DC/2DI/1GD5 and installed it on my ASUS Maximus IV Gene-Z motherboard. My motherboard has onboard graphics card with HDMI output as well and before it was fine, but after I connected my 23 inch monitor to the new graphics card part of my monitor isn't used until drivers are not loaded. So BIOS, console, windows installation and even windows (when driver is not installed) uses part of display and doesn't scale image to fit my monitor. Max resolution I was able to set from windows was 1280x1024. As soon as I install drivers it works fine, but BIOS and console are still running with that black frame. What's that? How to solve the problem? I don't even know what to google. Thanks in advance.
sounds like a combination of the driver scaling non-native resolutions up to native ones, and the monitor itself not scaling non-native images. usually it's the other way round, the monitor will only scale non-native sizes.
there is usually an option listed as '1:1 pixel mapping' or 'scale all sources' or similar. without knowing your monitor make and model it's hard to know, as different manufacturers use different terms. edit: on the NEC AS231WM it's called "expansion" in the 'TOOL' section (page 10 of http://www.necdisplay.com/documents/UserManuals/AS231WM_UserManual.pdf )
when it's plugged into the onboard GFX, go into the monitor menu and look for the info display where it displays the current resolution. If it shows the native resolution as the current res while you're in the post screen and early boot up then it's scaling before it gets to the screen. see what it displays when you have it connected to the GTX 560 in the same part of the boot sequence (when it has the black bars)
compare and contrast. The POST screen should always be something low like 640x480. it's then scaling which makes it fill the screen either in drivers, output hardware or by the monitor itself.
In your BIOS you must have an option like that:
Auto-Adjustement OR Fit To Screen
Try Changing DIV to VGA and vice versa
It could be the scaling setting in the graphics driver utility; in the past I've found that that setting is somehow persisted and then affects the display during boot time (e.g. BIOS, the windows loading screen). If it's set not to scale, that would cause the screens to be shown letterboxed, with the resolution pixels 1:1 with your monitor's native pixels.
Even if it's set to scale, maybe scaling up to the size of the new monitor is beyond the capabilities of whatever is set to do the scaling, in which case you should at least try the other scaling choices if there are some.
Go to NVIDIA Control Panel, from the Display part of the tree choose "Adjust desktop size and position", select the display, choose one of the scaling choices (Use NVIDIA Scaling, Use NVIDIA scaling with fixed-aspect ratio, Use my display's built-in scaling)
Similar settings for people with AMD/ATI cards: (this is probably out of date)
Go to Catalyst Control Panel, select the digital display, go to Attributes, and check the option to Enable GPU Scaling.
Note the default (read as "have to be used") resolution of your monitor: 1920x1080
Better will be to select this resolution (in own monitor settings, not in Windows at 1-st step), positon|resize image with hardware controls.
PS: Maybe, monitor driver also will be useful (for Windows, obviously)