Q I am sorely tempted to buy a new Retina 5K iMac, but am a little concerned whether the standard graphics card will have enough oomph to cope with such a huge display, and whether I would need more than 16 GB of memory for similar reasons?

A Apple offers offers two display cards for the Retina 5K iMac 27” with faster i5 or i7 processor, AMD Radeon R9 models with 2 or 4 GB of memory; the cheaper and slightly slower 3.3 GHz i5 version can only ship with a 2 GB AD Radeon R9 M290, though.

Most software should now be using library calls which are handled in the graphics card, using its GPU and attached memory, rather than consuming main memory. That is not always the case with laptops or budget models, which may take up to 1.5 GB from the main pool of RAM. You could also find some badly-behaved apps which use the main CPU and memory heavily, but they will not benefit from GPUs, and will struggle in any case.

So a Retina 5K iMac should not need any greater main RAM than your current system, say 16 GB; Apple’s pricing for the step up to 32 GB is currently high in any case. If you want the additional features of the more expensive graphics card, that certainly would be a good investment, though.

Updated from the original, which was first published in MacUser volume 31 issue 2, 2015, its final issue.