I found out recently, that setting ingame V-sync to adaptive 1/2 rate helps, it's not like 50% better, but from constant 100% I am at 70-90% and sometimes getting up to 100% but without huge and annoying lags, just fps drops (which is also not fun, but playable). Nonetheless, would be REALLY nice if respawn/EA would at least look into this, and with upcoming update imply some small patch. Not sure if this is relevant, but when I was near Gib ult or even near Gib at all I've noticed increase of CPU use and fps dropped slightly.
EDIT: I have downloaded latest windows update (which made me blue screen once for no reason), then set fps_max 65 in apex settings, disabled V-sync in game and I've noticed HUGE upgrade, CPU is sometimes jumping to 80% but in most cases it oscilates between 65-90%, no FPS drops at all, no lags, cpu and gpu temperatures don't go higher then 65-70° (not even close to maximum anyways). I really recommend to do win updates, driver updates and I've also added apex as exception for my antivir so it doesn't lag it in the background at all. Let me know if it helped any of you.