Macs Running Zoom

Over the past few weeks I’ve used Zoom on a 12" Retina MacBook, an ancient 13" MacBook Air, and, last night, a 27" iMac Retina 5K.

Zoom normally shows a maximum of (IIRC) 20 users at a time in Gallery view, but has an option to increase that 48 at a time. I’ve used that option on both the MacBooks, but on the iMac the option is greyed out, with a message to the effect that the processor isn’t good enough. I find that odd, given the specs of these machines:-

12" : 1.4GHz Intel Co re i7/8GB, Intel HD Graphics 616 1536MB
Air : 1.8GHz Intel Core i5/4GB, Intel HD Graphics 4000 1536MB
iMac: 3.3GHz Intel Core i5/8GB, AMD Radeon R9 M290 2048MB

Moreover, the Zoom screen on the MacBooks is for the most part pin-sharp, being grainy or blurry only as bandwidth and (others’!) camera quality permits, whereas on the iMac the usually brilliant retina screen looks, in Zoom, disappointingly blurry.

None of this seems to make any sense. The iMac and 12" MacBook both have Retina screens, and MacBook Air and the iMac both have Core i5 CPUs, yet both the MacBooks are brilliant for Zoom, whilst the iMac is a huge disappointment. All three machines are configured to display at their “recommended” (which I assume to be their native) screen resolution.

Is anyone able to shed any light on why the 5K iMac, with its renowned screen and graphics, should fail at what even an 8-year-old entry-level MacBook Air with its non-Retina screen does perfectly?

Cannot answer your question. My Retina iMac shows pages of 24 users at a time, though I’d be interested in knowing how to double it to 48. Image quality on the conferences I’ve been on have been fine on the Mac, though.

On my MBP, I’m able to see 5 rows of 5 for the maximum on my Retina display that is set at 2048x1280. I wonder if it’s a limitation of resolution or screen size?

Correction: on my Retina iMac I see 20 people per Zoom page @ 4 rows of 5 people, with my display set one ‘notch’ bigger than Default. I don’t know what that resolution comes out to, though, or if it actually affects contents of Zoom windows.

Zoom publishes which features are available for which types and generations of CPU. There are limitations (though I can’t recall them and I’m not with my computer at the moment) as to which computers can display how many concurrent other people. On my MBP 16", I can get the 48. It’s odd that such and old Air can do it though.

You say it’s odd that an old MBA can do 48 Zoom users per screen. I don’t think it struck me as odd, though it was certainly a pleasant surprise! But doesn’t it seem odder that although both machines use a Core i5 processor, the 5K Retina iMac can’t?

So far I’ve managed to avoid Zoom so I’m speculating here:

In terms of image sharpness could it be that the larger screen is showing up the imperfections more? The more area the image is spread across the more blurry and less detailed it will seem. Smaller ‘thumbnails’ of images always look sharper than when you open them up. Maybe it’s that bad everywhere it’s just that you can really see it on the larger 27" screen?

In terms of number of images you can see, are there any other distinctions between the systems? Are they all running the same version of zoom; all running the same version of MacOS? Any differences in the network speed they can access? Or speculating evening more wildly: You’ve not got a weird setup like running Mojave in a VM (as to use 32bit apps) & the VM is telling the OS it’s got a different processor than the physical machine has or anything along those lines?