Has anyone had this gfx card problem?

hi all, just wondering if anyone has had this: (I’m running flame 2021 on a iMac 27" (2014), in Osx Mojave)

all works well… but… I exited the flame just now and viewed my export on the desktop using Preview I guess or Quicktime, and the screen completely breaks up, into white bars and blocks of white, then flickering white screen at about 10hz… just about made it back into flame through the breaks in flicker to archive.
I shut down for 30mins reset the PRAM and it all seems to be ok again…

has anyone had this? just worried my gfx card is breaking,

any thoughts would be welcome
ta A.

Is it possible that the GFX card isn’t well seated in the slot? It does sound like a hardware thing

Hmmm…is this the first and only time this has happened? Any additional known changed sources of intereference? Any cables that may have been jiggled? If it doesn’t happen again then keep grinding away and getting your money’s worth. If you are adventurous you could see about opening up the case to blow some dust around.

thanks, its a 5k retina screen so getting inside requires unsticking the surround…

just a point to note … in the startup dialog… it says
VIDEO: monitor refresh rate measured as: 59.992864

would it be easier on the gfx card if I also used a project with 59.99 cfg file?

Hi there,
I had the exact same problem with a late 2014 iMac. My thought was also a faulty graphics card, but not sure.
Only happens when it runs hot. Shutting down and leaving it for a while seems to solve the problem momentarily.
My solution? I got a new computer for Flame. Now I use the iMac for syntheyes and a few other less demanding tasks.

And the heat is why popping it open might be worth it. I have 3 kids and a dog in an old house and the dust that ends up in my Mac Pro case after just a few months is mind boggling. iMacs are amazing machines but fall short in the active cooling department.