No video until Windows boots

I have just upgraded my system and was hoping the new Asus X99 Deluxe/3.1 would solve the issue I had with my old Gigabyte motherboard. The problem is that I cannot see the boot screens if I connect to the DVI-D port on my monitor but if I use its VGA port I can see the screens. Not really a problem if I only had one system but I have 3 systems connected through a KVM and that only offers DVI ports.

With the old Gigabyte motherboard I did a lot of experimenting and got some excellent support from Gigabyte even as far as setting up a test rig with same motherboard (at same BIOS level) and graphics card with photos of the boot screens and connected to the graphics card DVI port. So it looks like the problem is the monitor. It works through the HDMI port on the graphics card connected to my TV and worked through the DVI port on another monitor I borrowed.

However, I thought that it may have been some strange interaction between motherboard/graphics card and monitor, borne out when I bought a cheap graphics card that worked fine. SO was hoping the new motherboard with different BIOS may have resolved the problem.

Reluctant to but a new monitor yet as I've seen quite a few posts with the same problem but different motherboards, graphics cards and monitors. Was hoping somebody has seen this problem and found a solution.

It makes no difference taking out the KVM or using a VGA to DVI converter. I have also tried a DVI-HDMI converter and that makes no difference. But thanks for the suggestions. If I knew somebody with a monitor with HDMI converter, I think that would work and I'd just get a new monitor with an HDMI port. ALmost all of the issues I've found with a similar problem are DVI ports although a few have been with other types of port on the monitor.

Thanks for taking the time though. And the DVI port is fine as I have another couple of systems connected through my KVM and they both work fine. As I said, I think it is some compatibility issue between monitor and graphics card.