Opencore boots at too high a resolution.

Hi. I am trying to hackintosh an old Dell Optiplex 380 but I can't see the boot picker or setup screen because it is at way to high of a resolution. Both 1080p monitors I have give me a signal over range error, and the old CRT I have shows me a very glitchy, unusably small picture, which is how I know it got to setup. Is there any way of forcing a resolution? I tried the graphics mode boot flag to no avail. Thanks. Edit: forgot to mention I am using opencore 0.7.3