HDN/iMac graphics weirdness and crash

[Bookerv12]

Hi,
Doing this for a friend.

They have a 2 year oldish iMac, HD Native Tbolt box.
ProTools 12.8.3.
Sierra

I tried doing a search, but can't seem to find anything.
System worked great for 2 years.
No issues.
All plugins are updated.
I had them upgrade to 12.8.3 from 12.8.

When you do some quick editing, (trimming clips, chopping clips up, etc.)
The screen lags real far behind.
Sometimes, Protools unexpectedly crashes.

It reared it's ugly head after opening an older session, and now does it regularly.

We tried the P Gates trasher with no luck.
Any idea what may be a good place to look?

Thanks

[albee1952]

First thing to check(for me anyway) would be to go back to 12.8.3 and see if that clears it up.

[Bookerv12]

Hey,
Thanks.
They just went from 12.8 to 12.8.3.
It started doing it in 12.8.
We were hoping the jump to 8.3 would help.