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I brought a new monitor with identical res to iMac (2560x1440) so I could use dual monitors without the windows changing size as they are dragged from screen to screen. I plugged monitor in (with hdmi) the mac will not let me select 2560x1440 it only lets it goto 1600x900 when the screen is rated 2560x1440 I have tried pressing alt on the scaled button but nothing is working.
Jack Targett
Posted 2017-08-18T12:47:27.290
Reputation: 11
1Please provide the exact make and model of the monitor and your Mac’s model description (like “iMac (Retina 4K, 21.5-inch, Late 2015)”). – Daniel B – 2017-08-18T12:49:53.683
Philips Brilliance 272B (PHL 272B7QPTK) And the mac's screen is 27-inch (2560 x 1440), iMac (27-inch, Mid 2011), AMD Radeon HD 6970M 1024 MB – Jack Targett – 2017-08-18T12:54:03.583
1Your iMac does not have an HDMI output. What kind of adapter did you use? You should use a DisplayPort connection for optimal performance. – Daniel B – 2017-08-18T13:06:14.197
I just use a thunderbolt to cdmi. – Jack Targett – 2017-08-18T13:21:05.783
I found multiple posts suggesting your system is probably too old to handle anything higher than 1080p over HDMI. You might need a different adapter or use a different port. I've seen suggestions for display port and dual-link DVI. – Appleoddity – 2017-08-18T13:51:09.040
it can output 1600 x 900 or 1344 x 756 is that not higher than 1080p? – Jack Targett – 2017-08-18T14:51:03.510
1080p == 1920×1080. (Well, technically it just means 1080 rows, so it could also be 1×1080.) There may be additional issues because it’s not even reaching that resolution. – Daniel B – 2017-08-18T17:00:36.067