Re: XPS M1530 and 2560x1440 on U2711 with HDMI [SOLVED AND WORKING]
You don't need custom drivers. Just get the latest ones from the nVidia site, then create a custom resolution under nVidia settings / Change resolution / customize. Make sure you choose the right display to create for.
It didn't work until I updated my GT8600 M driver. Now it's working perfectly. Hope this helps.