The new 10.9.3 update to Mavericks offers improved support for 4K displays. Before the update, Retina MacBook Pros and the new Mac Pro were able to drive 4K displays, but using any resolutions below the monitor's native resolution would result in soft, slightly blurry-looking screen elements and jaggy text. The new resolution options and system optimizations in 10.9.3 make scaled resolutions look much, much better. …