I'm posting this because with all of the discussion about thunderbolt/no thunderbolt/ on the G-series laptops, I was never able to confirm that the mini DisplayPort would work fine as intended- as a mini DisplayPort!
In case this helps someone- I can confirm that my G75VW's (purchased in October) display port instantly recognized & connected to a Dell U3011 monitor & drives it at 2560x1600. Works great as a DisplayPort!
For what it's worth I ditched Windows 8 and am running Windows 7 64-bit now- so I don't know if it works as well under Windows 8 (but hope that it would, considering that the laptop originally shipped with Windows 8).