I'm using a 3900X, but the principles remain the same.
I started with a manual all-core OC, a manual per-CCX OC, and then PBO, in that order. Given that I'm thermally limited and that my manual OCs cannot get anywhere near PBO's peak boost clocks, my unconditionally stable manual OCs are only faster in very stressful all-core loads. I can do about 100MHz higher in Prime95 manually (or 125MHz on three of my four CCXes and 75MHz more on my weaker CCX) than I can get all-core PBO to boost to safely, but in pretty much every other scenario, PBO with either some manual tuning or ASUS' OC PBO presets are faster.
If I had better cooling, I'd stick with the manual OC because my all core OC would come very close to PBO's max low-thread boost clocks, but being thermally limited to about 170w peak means PBO is the better overall option.
Anyway, in your scenario, I'd reevaluate your PBO settings and see if you can improve it's boost clocks, if you can't an all-core manual OC is probably better..as long as temperatures and voltage are in check. gupsterg has already gone over the basics of dialing manual PBO settings and linked to Stilt's post on how to find the peak safe(ish) load voltage for your part, so no need for me to rehash that.
On a side note, any little bit of power or thermal budget you can save will improve how PBO functions. Once you get the basics dialed in, go back and set manual stock voltages for everything possible, except vcore and see if that's stable (and not losing performance to clock streching), then start undervolting things like the SoC and perhaps PLL. I get best performance results on my part with 1.05v SoC and 1.75v CPU PLL. Using the lowest LLC level (or turning LLC off) and then reducing VRM switching frequency to improve VRM efficiency can also help (you don't need to augment transient response when using stock load lines).
...rightful liberty is unobstructed action according to our will within limits drawn around us by the equal rights of others. I do not add 'within the limits of the law,' because law is often but the tyrant's will, and always so when it violates the right of an individual. -- Thomas Jefferson
Last edited by Blameless; 01-30-2020 at 01:44 AM.