Vermeer (overclocking, i guess?) Considerations

[Bloax]

Courtesy of a Good Fren, I got a 5800x in the mail about five days ago without blowing up my bank account.
So then, what's it all about?

Well first and foremost, the BIOSes (or at least, ones for my board) are rough around the edges -
here's a 2:1 memory:fabric ratio turned on, with a mismatched FCLK, on an innocent-looking DDR4-3200 XMP.
(program link)

So if you're an XMP warrior within reasonable memory speeds (3200-3800) right now, make sure to set your fabric clock to match half the rated memory speed manually -
if it does **** like this, that is; it's really bad for performance.

Now, once you get your **** in order
- I can't claim anything but the fact that this **** is fast.


As for making it go fast - clockspeed scaling likely depends entirely on what you're trying to do, but most things probably won't see much gain past ~4900 Mhz.
Fun thing about Zen3 though; PBO is no longer a semi-useless pile of Optimize For HEAT garbage on anything that isn't wood-tier silicon.
This comes as a result of the addition of a ""curve optimizer"" thingymabob:
Set a negative offset, and PBO will use a higher clockspeed at the same voltage, so long as we don't bump into the PBO limits.
These limits are important for coercing it into using a "lower" frequency at a lower voltage, e.g. 4550 Mhz at 1.25v instead of 4650 at 1.35v
The reason you'd "coerce" it into doing that? I can run x264 at 4775 Mhz with 1.28v.. Until my CPU hits 81 C, then it explodes.
Lower limits help with temperature, help with holding stable clocks! :---DDD


This, combined with the fact that there is little to gain from truly ridiculous frequencies, means that you can "dial in" PBO to behave like a good overclock - while keeping some "frequency spikes" where it does anything.

To get it to behave itself, you'll most likely not be setting the "max frequency offset" particularly high, if anything at all, as clockspeeds like 5000 tend to be very demanding in voltage - and very crash-prone if you have a high negative Curve offset.
But as long as you keep in mind that it's a (usually positive) tradeoff to keep the max boost "sane", you can push the Curve offset to ridiculous values - with some fine-tuning using low (+/- 5-15 mV) voltage offsets.

Sooner or later, you'll find PBO settings that run things no worse than manually dialing in freq/volt for a task, except with the presence of a ez-workload boost.

is this a CTR 2.0 hype-piece? maybe? idk

it's Fun
especially the part where Hard workloads are stable,
Light workloads are stable,
Videogame is stable,
but Windows Shutdown pops the CPU

 

[Bloax]

Here's an example of an average Curve offset of -24.75 - it varies a little core by core, I haven't completely figured out which cores are best, and your cores will be different from mine.

PBO limits were 114/96/112, I should probably raise them by something like +4, as 4.5 Ghz at 1.19v makes me queasy.

 

[Bloax]

For a short round-up:

PBO is now a super useful tool;
It always tries to hit the power limits you have set, which can get very hot.
If things get very hot, high clocks get unstable.

Ergo, try to keep the limit somewhere around where your cooler performs very well (around 75 C seems fine?) - then push the negative Curve offset like crazy.
Cure instabilities or pesky inefficient voltage use with a tiny voltage offset.

optional:
Figure out where your cores crash at 1.25v doing a very light workload - in my case, it was a 4925-4975 range spread between the various cores - then adjust your Maximum Boost Offset accordingly.
e.g. I'm running +50, probably should raise it to +75, on my 5800x which lets it boost up to 4900 Mhz.



fun fax: 2000 fclk has thus far not performed better than 1900 for basically anyone, but 1933 with the exact same memory settings (using 1.63v instead of 1.58v) does perform a little better In Videogame(tm)

2033 fclk, 3800/1.1v
encoded 15000 frames, 125.76 fps, 8934.36 kb/s hmmmmmmmm
2000 again
encoded 15000 frames, 177.73 fps, 8934.36 kb/s
lol
1900 fclk
encoded 15000 frames, 175.14 fps, 8934.36 kb/s

testing good