we have about 30 rigs- all amd -all windows 10 ghost spectre (no updates no bloat no telemetry)
been trying 5.7b with the -clkernel 3 option

all the rigs that are "on the ragged edge" showed no improvement.
eg a nice rx580 rig thats fully tuned and gets 185 megahash for over a year now - no improvement
all the shagged old gpus that are core 950 and mem 1800 wont take clkernel 3 at all

but the polaris gpus we have that are not on the ragged edge show a very slight improvement with clkernel 3

if you dont want to break a gpu set -ttli70 (or even lower) - we ran through the recent uk heatwave with no breakages

if you have reboot.bat and -rmode 2 your rig will reboot if a gpu hangs - very useful
if you watch you can see which gpus fail with clkernel 3 and set them to clkernel 1
so if gpus 1 and 6 don't like it you set
-clkernel 1,3,3,3,3,1
also if your gpu is running a screen its more likely to not like clkernel 3

hope this helps someone
ps fave gpu is still sapphire nitro rx470 all ours get 30 megahash but only require one 6 pin power cable