One thing that's important to note for people who are saying it's too big. It's about the same vertical height as all the other 27"/28" monitors, like the Thunderbolt Display or the Samsung 28", it's just wider. My guess would be most people would typically run this in a 1.5x scaled 2730x1440 mode, since the 28" 4K monitors are currently best run (IMHO) in 1.5x scaled 2560x1440 mode. Think of it as a slightly wider version of the Thunderbolt Display but with better resolution.
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Are you saying Yosemite won't handle the other scaling modes at all or that they're broken?
I'm not sure if it's Yosemite's fault - Graphics driver issue since it's so new (on my system that uses NVIDIA Web Drivers) or what...
But right now the only 2 resolutions that work and look correct (in terms of aspect ratio) are:
1x (no scaling) at full panel resolution of 4096x2160
2x (perfect Retina mode) of 2048x1080
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I'm also a bit confused by what you mean. I would be running this at native 4096x2160 @ 60Hz. Are you saying that doesn't work correctly, and you are forced to go to the 2x retina mode? Or does it run at native resolution on OS X just fine?
See my last post
UPDATE: New web drivers just came out
These are working (all at 60hz):
4096 x 2160
3008 x 1692
2304 x 1296
2048 x 1080 is absolutely the best (as expected - perfect 2x to native panel resolution)
Also - The new drivers are allowing for correct resolution aspect ratios at all other scaled resolutions.
If you choose one that's not 17:9, you'll get black bars on the side or stretching (your choice in Monitor hardware Menu)
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The colors on this display are SUPERB.
Also, I've had a ton of IPS monitors over the years and this is probably the least amount of IPS glow I've ever seen.
I wouldn't bother waiting around for an Apple standalone 4k/5k display (which will probably be at 5k) as that's a ways off due to bandwidth issues (will need newer DisplayPort Standards to be in the wild -- and Mac's will need hardware upgrades to do all that)
This is *the* monitor to get right now (in my opinion)