Wait, how does Ryzen overclocking even work again?

[pipnina]

So I just watched the der8auer video on overclocking the 5950x with an ASUS Crosshair VIII and the "amp-based OC mode toggle", and realised I never knew until now that there was no way to scale overclock profiles based on the number of active cores, and the way overclocking worked even with the ASUS board's features enabled seems a little confusing to me.

 

On my 6700k, it seems like I can kinda just dial up the multiplier and my CPU will lock itself to 4.5 instead of the 4.00 it goes to by default. But with Ryzen you disable single core boost by overclocking on all cores by default? And he was scratching 5.0GHz with a 280mm AIO in single core, and 4.0GHz with all 16 cores. And then it took LN2 on a beastly overclocking board for him to get past 5GHZ on all 16 (although by that point he reached 5.8).

Is it even worth buying a Ryzen 3000/5000 with the intention to overclock it if it needs a £350 motherboard to get beyond the default boost without sacrificing huge levels of single core perf? Is the 4.8/4.0 boost the best you can get without seriously splashing out on motherboard and cooling for a 5900x/5800x?

 

I'm not all that caught up on how the OC scene is at the moment. Like I said the last I knew, bumping up your multiplier just straight up gave gave you more performance everywhere and you could get a fair bit of headroom just by having a mid-high tier air cooler or a 140mm AIO.

[Chris Fortune]

For me unless the purpose of the system is to overclock it I would try to buy what can do the job out of the box

[Letgomyleghoe]

26 minutes ago, pipnina said:

s it even worth buying a Ryzen 3000/5000 with the intention to overclock it if it needs a £350 motherboard to get beyond the default boost without sacrificing huge levels of single core perf? Is the 4.8/4.0 boost the best you can get without seriously splashing out on motherboard and cooling for a 5900x/5800x?

raw clock speed isnt all that is put into the calculation of single core/thread speed, IPC improvements is what keeps ryzen competitive for gaming, not just clock speed alone. but if your only goal is to overclock, no its not worth it, go buy a FX if you strictly want to overclock.

[Master Disaster]

27 minutes ago, pipnina said:

snip

The Zen 2 (and newer) architecture is different to Intel in how it handles boosting, when the system is idling Zen will boost the fastest core in each CCX up to much higher than the CPU can handle on all cores (for example, my 3800X can do 4.5Ghz on all cores but I've seen it boost one core up to 4.8Ghz). It does this to speed up the high frequency low intensity tasks that the OS will be doing pretty much all of the time however it also requires the CPU to use a fairly high voltage on the fastest core, again much higher than one core would ever normally use.

 

When you force an all core OC the CPU is forced to disable single core boosting because of voltage constraints. By locking all cores to a high clock you're also significantly increasing the voltage it needs to run stable and there is no overhead left for it to also boost the fastest cores beyond the OC, the overhead for single core boosting comes from the other cores downclocking.

 

I've been saying this since I got my Zen 2 and a few months back Jayz2Cents did a video covering it too. OCing Zen 2 is pointless unless you're on the extreme side with your cooling. Its very rare you can force an OC that's higher than the CPU can automatically boost too and by forcing an all core OC you're throwing away single core performance. The best thing to do with Zen 2 is leave it alone, if you must OC then use PBO.

[pipnina]

25 minutes ago, Master Disaster said:

The Zen 2 (and newer) architecture is different to Intel in how it handles boosting, when the system is idling Zen will boost the fastest core in each CCX up to much higher than the CPU can handle on all cores (for example, my 3800X can do 4.5Ghz on all cores but I've seen it boost one core up to 4.8Ghz). It does this to speed up the high frequency low intensity tasks that the OS will be doing pretty much all of the time however it also requires the CPU to use a fairly high voltage on the fastest core, again much higher than one core would ever normally use.

 

When you force an all core OC the CPU is forced to disable single core boosting because of voltage constraints. By locking all cores to a high clock you're also significantly increasing the voltage it needs to run stable and there is no overhead left for it to also boost the fastest cores beyond the OC, the overhead for single core boosting comes from the other cores downclocking.

 

I've been saying this since I got my Zen 2 and a few months back Jayz2Cents did a video covering it too. OCing Zen 2 is pointless unless you're on the extreme side with your cooling. Its very rare you can force an OC that's higher than the CPU can automatically boost too and by forcing an all core OC you're throwing away single core performance. The best thing to do with Zen 2 is leave it alone, if you must OC then use PBO.

So when cooling Zen2/Zen3, without the intent to overclock, there isn't any reason to go far beyond what AMD recommends already? If so, that could at least save me some money as I was planning on getting a hefty Noctua D15s. But if something half the price will be plenty good enough I might as well skimp out there.

[Master Disaster]

7 minutes ago, pipnina said:

So when cooling Zen2/Zen3, without the intent to overclock, there isn't any reason to go far beyond what AMD recommends already? If so, that could at least save me some money as I was planning on getting a hefty Noctua D15s. But if something half the price will be plenty good enough I might as well skimp out there.

Correct however its always better to have it and not need it than to need it and not have it plus the other benefit of your Noctua is near silent operation.