Flickering how? If you can make a video then great but more info is going to be needed. With that sort of spec I imagine you are not using VGA but I would like to know what connection type you are using.
It could be one of a few things depending upon how it flickers. Do you have another monitor/TV you can try? Alternatively do you have something else you can plug into the monitor/TV you are using to test it out there? Backlight on the monitor on the way out is a fairly popular one, I see it often enough in TVs and laptops beyond a certain age and occasionally before then as well. This will look like the thing dimming (or brightening which is not good if so) and coming back.
If it black screens for a second or so then we usually look more to the graphics chip/path or something there.
If it distorts the image for a second, in various ways this can be including an almost freeze, certain sections updating, sections going out of line with the rest of the image, then if it is a digital signal we also look at the graphics setup and possibly the screen as well. If it was a nice old analogue connection then there are some alternatives there.
Does it happen randomly or when you launch certain programs/games/do certain things? All the time or just some of the time when doing certain things? Does it do it from boot or only after it has been on for a while? All resolutions or just the one you are on? Do you have anything else in the path (no amp or anything you feed your PC into or similar)?
I will warn you that it is not likely to be good with digital signals on modern hardware, though you might get lucky and find it was the drivers or something.