Connecting a 2560x1440 display to a laptop?

I am successfully using a Korean 27" IPS display (Crossover 27Q) at 2560x1440@60Hz in Linux over a VGA cable, with an old (GM45) Intel chipset. To my surprise, the hardware can drive the image just fine at that resolution over VGA. The image is relatively sharp, but there are some "ringing" artifacts to the right of hard intensity transitions.

The most surprising thing though is that a second, brand new Belkin VGA cable I bought could not drive the monitor at full resolution. I don't know if it's because the first cable has those ferrous blocks on both ends to cancel RF noise, or if there is a wiring difference between the two cables, or if there is a difference in electrical characteristics of the wires, but the EDID of the monitor can't even be probed, so Linux doesn't know what modes the monitor supports with the Belkin cable, and will only drive it at a much lower resolution by default. I had no idea there was a difference between high-end and low-end cables.

I also tried the display with a Mid-2012 Macbook Pro with Intel HD 4000 graphics. The display only runs at 1920x1200 over both HDMI and DisplayPort-to-DVI with a Dual Link DVI cable. Apparently the chipset and the DisplayLink ports support 2560x1600 for Apple products, but not for third-party products. Probably running Linux or similar with HD 4000 you would have more luck.

Ivy Bridge HD 4000 (the most likely used Intel laptop video) is limited to 3 displays. One is required to be a DisplayPort 2560x1600, one at up to 1920x1200 and 3rd one is HDMI.

Normally, HDMI is 3rd port, and it is limited to 1920x1200. So laptops are simply limited. If there is no DisplayPort on laptop (it is always out there on chip, but may be not on the motherboard) then it is end of story.

http://www.tomshardware.com/reviews/ivy-bridge-benchmark-core-i7-3770k,3181-3.html