Hi Neil, I read this with interest as I too have found the adaption of external monitors with Mac’s a bit hit and miss.
As a test, do you have on hand a late model Mac/Macbook you could see if the later OSX is smarter in this sense and how it recognises the external monitor when you plug it in using the leads you currently have and get the quick systems report for the connected monitor. Your 2009 Mac is certainly high spec but by being 2009, it is held back to older OSX versions and perhaps this may be the issue. You may have to get yourself a late model iMac but I wouldn’t resort to that yet. Pete. > On 25 Mar 2022, at 1:48 pm, Neil Houghton <n...@possumology.com> wrote: > > OK, here is the iMac setup: > > Late 2009 27” iMac – top configuration, 2.8 GHz core i7, Graphics ATI Radeon > HD 4850 512 MB > iMac has been reconfigured with 250 GB SSD, 3TB internal drive and currently > 20GB RAM > Currently running El Capitan OSX 10.11.6 > > With the SSD and RAM upgrade this is still pretty snappy and I am frequently > running multiple Excel spreadsheets and/or multiple browser windows with many > tabs in each – which took me to a second monitor. > > For a while I had a 27” full HD 1920x1080 monitor running, which all worked > fine but I found the discontinuity of tracking from the 2560x1440 iMac screen > to the 1920x1080 monitor screen sufficiently annoying that I ended up > reducing the iMac resolution to 1920x1080 to match the monitor – which I > found much more useable. > > However it seemed a shame to have to resort to downgrading the iMac > resolution – so, given that the iMac can support video output up to 2560x1600 > - I decided to upgrade the monitor! > > I found a good deal on a 31.5” monitor with 2560x1440 resolution – the same > as the iMac native resolution this was the product (though it was only $355 > when I bought it) > https://www.amazon.com.au/gp/product/B08J3S6BT4 > <https://www.amazon.com.au/gp/product/B08J3S6BT4> > > I was pretty happy when after promising delivery by March 30 to April 11 they > actually delivered it yesterday – 2 days after I ordered it! > > So all setup and ready to go – and it is all working fine EXCEPT, despite the > monitor having 2560x1440 resolution, the maximum resolution offered in the > OSX display preferences is 1080i, ie 1920x1080 and a quick systems report > shows that the iMac recognises the display as: > LEN D32qc-20: > Resolution: 1920 x 1080 @ 60Hz (1080i) > Pixel Depth: 32-Bit Color (ARGB8888) > Mirror: Off > Online: Yes > Rotation: Supported > Interlaced: Yes > Television: Yes > > In my setup the monitor connection is by a direct mini display port to hdmi > cable (no adaptors) as this was readily available when I bought my previous > monitor. > > I have googled this and find that this is not an uncommon problem and not > specific to any particular monitor but seems to be a problem with the Mac > recognising the availability of the higher resolution of an attached monitor. > People seem to have mixed success in resolving this problem but some seem to > have more luck with Display port connections, rather than hdmi, recognising > higher resolutions and this monitor does have a display port input as well as > hdmi. > > So, I guess, the question is – does anyone have any experience of driving > higher resolution monitors from older imacs? Is buying a new cable such as > this: > https://www.amazon.com.au/Rankie-DisplayPort-Cable-Resolution-Ready/dp/B00YOQYQWY > > <https://www.amazon.com.au/Rankie-DisplayPort-Cable-Resolution-Ready/dp/B00YOQYQWY> > or this: > https://www.officeworks.com.au/shop/officeworks/p/comsol-displayport-to-mini-displayport-4k-cable-2m-comdpdp020 > > <https://www.officeworks.com.au/shop/officeworks/p/comsol-displayport-to-mini-displayport-4k-cable-2m-comdpdp020> > > likely to solve my problem? > > Any feedback gratefully received! > > Cheers > > > Neil > > -- The WA Macintosh User Group Mailing List -- > Archives - <http://www.wamug.org.au/mailinglist/archives.shtml > <http://www.wamug.org.au/mailinglist/archives.shtml>> > Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml > <http://www.wamug.org.au/mailinglist/guidelines.shtml>> > Settings & Unsubscribe - > <http://lists.wamug.org.au/listinfo/wamug.org.au-wamug > <http://lists.wamug.org.au/listinfo/wamug.org.au-wamug>>
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