Beginning with 2018.3 (the first 2018.x version I used) I've noticed the waveforms have gotten much much slower.
I mostly work without waveforms, but frequently engage the "show marked waveforms" to look at specific zones. In previous versions of Avid if I accidentally turned on waveforms with a large selection, it would slow down the system, but I could quickly hit my hotkey and turn them off.
Beginning with 2018.3 I found I often could not turn of the waveforms – I often had to hit my hotkey twice. The waveforms were also delayed – instead of drawing them one by one it seems like avid is buffering or something (I don't know) but I often feel like I do not have waveforms on but then realize that I do, but Avid is waiting (?) until it has more to show me perhaps?
Anyway, this was annoying but manageable. Enter 2018.8 and the "live timeline". This is almost unusable for me so far. If I happen to accidentally select a large chunk (say 30 mins) and turn waveforms on, I might have to wait 30 seconds before I can turn it off. If I happen to hit play then it's game over - Live Timeline takes over most of the CPU and the waveform draw routing takes over the west and the Avid is essentially crashed (but playing). I can wait for the sequence to end, or maybe gain control in a few minutes, or just force quit.
Unacceptable.
Avid, please fix your waveform problem.
iMac Pro (2017) 32GB RAM. Yes, I 've tried new user settings.