crash course on enabling PCB/XFR auto o/c for ryzen 2

[chrcoluk]

Thanks

 

[chrcoluk]

so I done bit of reading and this seems perfect, I will enable it today if I figure out how.

My watt meter is reading 45-50 watts total power draw even when compiling code. So cpu is well within TDP easily.

But ESXi I think is keeping all cores busy so traditional turbo isnt kicking in, so if I understand right PB2 and XFR2, will boost the clocks regardless of how many cores are active as long as there is TDP and temperature headroom, this sounds much better than traditional turbo mode.

The problem is I dont know what the live clocks speeds are, esxi is kind of crappy in this respect, lack of hardware monitoring, it is one of the reasons I want to migrate this home lab to proxmox. If I find out esxi is overiding bios turbo behaviour and thus preventing xfr and pcb2 to work, I will probably move to proxmox sooner rather than later.

 

[chrcoluk]

The problem is the cpu wont go above 3.6ghz, its not going in turbo at all.

I have found PBO in the bios which was on auto, I changed it to enabled.

But there is nothing in there for core performance boost or XFR or XFR2.

Reddit seems just full of confused people.

There is a mixture of others like me trying to get it working, some who say its on by default (makes no sense given it breaches cpu spec when on), reviewers stated they turned it on (so also kinda goes against the default is on theory), also a guy said its off by default on asrock and turned it on but he didnt say how he turned it on.

 

[chrcoluk]

Is that correct? I thought it basically would just boost to whatever the board will throw at it? I'd be happy to run mine enabled if I knew I wasn't killing my chip. It's really the only drawback of these chips, in that they are crap when it comes to clockspeed in general and overclocking. Hopefully the new non mobile based node will mean it's more back to traditional overclocking you'd expect with say an Intel.

How do you enable it then? thanks.

My chip is nowhere near TDP limits. Total system power draw is under 50 watts and its a 95 watt chip. I load up only 1-2 cores and it stays in stock speeds.

 

[chrcoluk]

Well enabling PBO has added about 10% to cpu performance so the auto is disabled, and I can confirm the method I am using to check on cpu clock speed is a no go in esxi. I may need to find a live windows boot disk or something to do some proper testing.

 

[chrcoluk]

Done testing in windows bare metal.

It will downclock to 2.2ghz on idle.

But there is absolutely no kind of turbo functionality working. 3.6ghz max clock logged.

I tested with the PBO on and off.

The voltages are very nice compared to intel and temps, I am thinking now whether to just set a higher static clock speed as an overclock, leave it alone and accept no turbo etc. or try to get the proper auto o/c aka turbo working.

I wonder if anyone ever confirmed turbo even works on b450 instead of just assuming it does?

 

[chrcoluk]

Have you looked at guides for your motherboard on how to enable XFR?

I tried to look for guides and there isnt any LOL

But some good news.

I flashed the 1.00 bios (was 1.50) for the board and reset bios to defaults and BAM I now have turbo clocks, also I can confirm PBO Auto setting is disabled, after I set it to enabled the board locks to -0.1v offset and gets higher clocks.

Because of the offset the temps are actually lower in both idle and under load with PBO enabled.

 

[chrcoluk]

all cores I get about 4.05ghz now and 4.25ghz one core.

Thats with -0.1v offset. So pretty happy with this.

My next step is to see if esxi actually uses turbo mode as I suspect it doesnt due to its scheduler. So I am planning at some point to migrate the box to proxmox.

 

[chrcoluk]

For the curious on the AMD cooler, which looked like this but I still installed it, temps max out at 62C on cinebench. Idles at about 31C. Noise is no worse than the 3rd party cooler I had on the i5 750.

 

[chrcoluk]

I think XFR/PBO is a case of Off, Auto and Enable. Auto boosts to within the CPU's power parameters and if you set to enable, it's down to how strong the motherboard VRM's are, however it will up the voltage outside of AMD's 'safe' settings. I tried it, was getting spikes of 1.51vcore and generally sat over 1.4vcore when under load, so put it back to auto. Performance was increased for sure, but nothing mind blowing so best left alone imo. If ASRock updated their BIOS to have a level of XFR for less to more extreme modes, that would have been better.

Basically, I'd leave overclocking alone on these unless you need an all core OC, then do it to 4.2 if worthwhile... for me it wasn't, as I only really game on my machine so need the single cores boosting as high as possible.

I have now disabled PBO again, did some more reading up on it.

So as I understand it now PBO is basically PB2 but disregarding TDP and some other spec'd limits. I applied the -0.1v offset manually to keep those undervoltage gains and will keep it like that as far as the bios is concerned.

There is a slight dropoff without PBO now when keeping the offset but its very low.

Multicore cinebench

PBO on 1382
PBO off 1364

Singlecore cinebench

PBO on 171
PBO off 168

The way this stuff is named I think can easily confuse people, but I guess as people get used to ryzen more and more it will become easy.

 

[chrcoluk]

Tested in linux, linux it seems doesnt recognise turbo clocks in the kernel readings, however it has a flag where you can toggle boost and with toggling that I confirmed boost works in linux.

I now know how to disable XFR/boost in the bios, so for ESXi I will run some benching in a guest, then reboot into bios, disable boost, and rerun same tests to see if they drop down.