According to available information (because AMD does not provide publicly info how their products work), gpu clock should be set between game clock and boost clock (while gaming) for Navi architecture.
But Radeon drivers (adrenaline) have boost clock always set to 2100, which is in my opinion incorrect. It is very obvious becuase I have Sapphire 5700XT that should boost "up to 1925MHz", but it boosts indeed much more higher - to 2100MHz which is set in drivers.
E.g. common boost is e.g. 1950 in lighter load, with death boost spikes to 2100Mhz, max should be 1925 according to manufacturer and GPU-Z.
And it explains various issues and random behaviour of crashes. Crash occurs often when sudden death boost occurs. And it depends on quality of chip if card crashes at these boosts, so it explains why some people do not have any issues - depends on distribution of gpu chips.
I underclocked my card in Adrenaline and now it is much more better. I am testing it yet.
Still I think that something is massively broken in drivers now, maybe all boost architecture, becuase I read in some articles that card does not have clock set? I do not know AMD does not provide info how things work.
I was able to Google info from AMD site, AMD says
Boost Clock Frequency is the maximum frequency achievable on the GPU running a bursty workload. Boost clock achievability, frequency, and sustainability will vary based on several factors, including but not limited to: thermal conditions and variation in applications and workloads.
Therefore AMD driver setting 2100MHz boost frequency for all 5700XT cards must be incorrect. AMD drivers cause frequency higher than manufacturer boost frequency normally with boosts going straight through the roof towards deadly 2100MHz.
Just for comparison from what I read on sites, it looks like AMD boost frequency is maximum frequency (there is always up to, e.g. up to 1905MHz in specification) whereas Nvidia technology boost frequency means minimum boost frequency and is dynamically overclocked to hit power and temp target.
So again if this is how it works - Radeon drivers should not set boost frequency 2100MHz for each and every 5700XT card.