Including with your tongue in your left cheek and your eyes squinted?
If that's the case, then, I'd be asking for my money back.
Seriously, it could well be that you have one with a slight operating difference due to a different batch or internal components, etc.
Other than that, can you connect all 3 monitors using the same method for each: ie; using 3 HDMI leads without adapters? Or all 3 via DVI?
I have an ASUS Republic of Gamers card with 3 DVI slots [and a Display Port], but usually graphics cards do not come with 3 of the same connnection, so I'm thinking maybe not. Unless you have another card with 3 DVIs that you can use to test the theory.
But yeah, that may be a contributing factor, 3 different connection methods, with the DVI to HDMI being the weakest link, and therefore not producing such a strong signal as the other 2, higher value connections. Other than that I'm out of ideas.
Anyhow, all the best with it.