1440p means 2560x1440 resolution. A "better" resolution for 27" monitors in some people's opinion. With 1080p (1920x1080) on a 27" monitor the pixels are very obvious; a 1440p 27" provides a higher pixel density and thus a crisper image.
IPS means In-Plane Switching, a display technology that produces better color representation. Usually preferred for photo and video editing.
Skylitfly's response is akin to saying you should buy a 6-cylinder motor pickup truck when you've asked for advice on why your Honda Civic doesn't run smoothly. Certainly a worthwhile opinion to consider when you buy your next monitor, but not particularly helpful to the matter at hand.
Have you gotten rid of the Displayport to DVI to HDMI chain yet? If not, please do so and report back.
(make sure you have a DVI input on the monitor before spending money on a single minidisplayport to dvi cable... I think your monitor is HDMI input only, so you need either a minidisplayport to hdmi cable or a minidisplayport to hdmi adapter then hdmi to hdmi cable)