*** AMD "Zen 4" thread (inc AM5/APU discussion) ***

[Steedie]

Chip definitely runs hotter than my 5950x did, but not as hot as I was expecting given some of the alarmist thumbnails on youtube.

Played a 4 hour session of Division 2 last night and with my AIO (360mm) on full whack, it sat at 85 for the majority of the session, only getting to as high as 88 by the time my room had gotten quite warm and the liquid temps had risen. Haven't seen it get in to the 90's yet, but I'm not running Cinebench or anything like that, so I'm sure it would if I ran something that maxed all cores

 

[Ayahuasca]

Chip definitely runs hotter than my 5950x did, but not as hot as I was expecting given some of the alarmist thumbnails on youtube.

Played a 4 hour session of Division 2 last night and with my AIO (360mm) on full whack, it sat at 85 for the majority of the session, only getting to as high as 88 by the time my room had gotten quite warm and the liquid temps had risen. Haven't seen it get in to the 90's yet, but I'm not running Cinebench or anything like that, so I'm sure it would if I ran something that maxed all cores

That is quite toasty for gaming mind but still within spec. Could always set up a profile for gaming at a lower power, you can lower temps 10-20c and not suffer any real performance drop.

 

[Steedie]

That is quite toasty for gaming mind but still within spec. Could always set up a profile for gaming at a lower power, you can lower temps 10-20c and not suffer any real performance drop.

Yeah I think last night was just to see what it would do at stock. My 5950x was undervolted pretty much since day one, and I'll likely do the same to this one today

 

[Journey]

Yeah I think last night was just to see what it would do at stock. My 5950x was undervolted pretty much since day one, and I'll likely do the same to this one today

I think already as proven there is a huge amount of potential for the 7950X to drop nearly half the watts and stay at the same sort of speeds, and thus having much lower temps.

 

[Steedie]

Right...

Really quick findings but...

3 minute Cinebench runs
Stock: 38315, 95c the entire time (5.15GHz)
Curve Optimiser set to negative 15 on all cores: 38221, 95c the entire time (5.15GHz)
Curve Optimiser and PPT Limit to 125w: 34989, 63-65c the entire time (4.7GHz)

Well impressed with that!!

Will tinker a bit more during the day but to get that score at that peak wattage is really impressive

 

[LtMatt]

Right...

Really quick findings but...

3 minute runs
Cinebench stock: 38315, 95c the entire time (5.15GHz)
Cinebench with Curve Optimiser set to negative 15 on all cores: 38221, 95c the entire time (5.15GHz)
Cinebench with Curve Optimiser and PPT Limit to 125w: 34989, 63-65c the entire time (4.7GHz)

Well impressed with that!!

Will tinker a bit more during the day but to get that score at that peak wattage is really impressive

Very nice!

Will be building my system over the weekend so will share my results once done.

 

[wookiee87]

Very nice!

Will be building my system over the weekend so will share my results once done.

i was planing to be built soon but my ek block is on pre order, have to wait until the end of october before i'm up and running
just noticed something mad with my asrock taichi, the cpu vrm heatsink has a active fan hidden away around the I/O section, small cutouts in the top just reveal it, guessing a 16 core at full chat can make em rum hot?

 

[LtMatt]

i was planing to be built soon but my ek block is on pre order, have to wait until the end of october before i'm up and running
just noticed something mad with my asrock taichi, the cpu vrm heatsink has a active fan hidden away around the I/O section, small cutouts in the top just reveal it, guessing a 16 core at full chat can make em rum hot?

I'll be going with an Arctic 360 AIO and I'm probably going to put liquid metal on the processor lid too. I've bought some electrical tape to protector the gaps in the CPU too.

Not sure about the fan first I've heard of it. I've heard the VRSM are all overkill according to Bullzoid, not sure why there is a fan in the Asrock board. As far as I know none of the others have fans.

 

[LtMatt]

There is some headroom for fine tuning to increase performance with curve optimiser.


Source: Igor

 

[Perfect_Chaos]

I had a reply yesterday from Kingston regarding buying RAM without EXPO for anyone interested

Thank you for contacting Kingston Technology.

Our TRG department advises the following:

AM5 boards from most manufacturers will support both XMP and EXPO profiles.
There should not be a need to adjust any timing manually, just select the profile in the BIOS.
For 6400MT/s support, you will have to check the QVL list of the selected board, if there is any 6400MT/s supported modules listed then KF564C32RSK2-32 should also work.
If not, then XMP profile #2 is set for 6000MT/s and should be supported.

 

[timorous]

What? I don't even know what the heck you are saying. You said they will burn if they don't drop wattage, which is not the case, since I can run CBR23 for 500 hours with unlimited TAU. Therefore, you are wrong on that account.
As i've said yesterday, and evident by the graph you just posted, the 12900k at stock configuration is more efficeint than the 7950x at stock configuration

That will depend on the motherboard and what it defaults the tau settings to.

Some will have the limit in place and behave like that others will have it default to unlimited. Depends on the motherboard.

 

[Grim5]

Right...

Really quick findings but...

3 minute Cinebench runs
Stock: 38315, 95c the entire time (5.15GHz)
Curve Optimiser set to negative 15 on all cores: 38221, 95c the entire time (5.15GHz)
Curve Optimiser and PPT Limit to 125w: 34989, 63-65c the entire time (4.7GHz)

Well impressed with that!!

Will tinker a bit more during the day but to get that score at that peak wattage is really impressive

Just:

1) Enable PBO
2) Set temp limit to 85c or 75c
3) Create small voltage offset (0.1v or so)

That will bring temps down and keep stock performance, unless your happy giving up 4000 points

 

[gbgt2]

I think already as proven there is a huge amount of potential for the 7950X to drop nearly half the watts and stay at the same sort of speeds, and thus having much lower temps.

Aren't these chips designed to be pegged at 95c regardless of cooling though? Not saying that undervolting isn't worth it if you can maintain the same performance but high temps in gaming aren't a "problem" as far as I understand it

 

[uscool]

Aren't these chips designed to be pegged at 95c regardless of cooling though? Not saying that undervolting isn't worth it if you can maintain the same performance but high temps in gaming aren't a "problem" as far as I understand it

Yes but some enjoy the tuning tweaking part , I personally enjoy that

I personally couldn't leave it at stock knowing I could improve without having to lose performance

 

[Journey]

Aren't these chips designed to be pegged at 95c regardless of cooling though? Not saying that undervolting isn't worth it if you can maintain the same performance but high temps in gaming aren't a "problem" as far as I understand it

They are designed to take advantage of all of the thermal headroom, and will keep boosting until they hit that 95c, however that is done with a largely aggressive voltage boost algo, and depending on silicon lottery similar results can be achieved (to stock perf) with manual adjustments to the voltage, resulting in lower temps and much lower power draw.

 

[humbug]

Right...

Really quick findings but...

3 minute Cinebench runs
Stock: 38315, 95c the entire time (5.15GHz)
Curve Optimiser set to negative 15 on all cores: 38221, 95c the entire time (5.15GHz)
Curve Optimiser and PPT Limit to 125w: 34989, 63-65c the entire time (4.7GHz)

Well impressed with that!!

Will tinker a bit more during the day but to get that score at that peak wattage is really impressive

That's 91% of the performance for 55% of the power.

 

[RBImGuy]

Aren't these chips designed to be pegged at 95c regardless of cooling though? Not saying that undervolting isn't worth it if you can maintain the same performance but high temps in gaming aren't a "problem" as far as I understand it

Manually tweaking allows to finetune power and thermal.
out of the box is a set default and can be to aggressively done.

 

[KompuKare]

Gonna taken a guess at why the techpowerup 7700X results appear different to those in many other reviews, e.g Techspot.

They weren't using a particularly high air end cooler (Noctua NH-U14S), and it looks like it may have been thermal throttling:

AMD Ryzen 7 7700X Review - The Best Zen 4 for Gaming

With the Ryzen 7 7700X, AMD is introducing their fastest Zen 4 processor for gamers. In our review we found out that gaming on the 7700X runs better than the 7900X and 7950X, thanks to the single CCD design of the 7700X. Just like on other high-end AM5 CPUs, temperatures are a problem though.

www.techpowerup.com

In their review, the 7700X peaks at 94 Celsius with this cooler. If that's correct, it implies that it may be neccesary for many people to configure PBO2 undervolting and temp limits to get the best out of their CPUs.

I though 94°C / 95°C is their new boost temp: that is while the temp is not higher than 95°C it will boost clocks until that point. So temps don't tell you the real clocks as a poor cooler might hit 4.6GHz at 95°C, a good cooler might hit 5.0GHz at the same 95°C, while an excellent cooler might hit 5.5GHz. (All numbers plucked out of the air to give an example!)

And that's before the silicon lottery is taken into account. Just what could theortically happen with the same silicon using different coolers. Like when Nvidia moved to their boost thing, predictability has gone out the window.

 

[Bencher]

I though 94°C / 95°C is their new boost temp: that is while the temp is not higher than 95°C it will boost clocks until that point.

Nope, that's marketing nonsense that amd came up with to not get any flak about these scorching hot cpus. If you cool them properly, they won't boost until 95c, just like any other CPU. The problem here is that's its almost impossible to cool them properly at these monstrous wattages and with that heat density, so in most cases it will thermal throttle before it power throttles.

TLDR : Zen 4 works like any other CPU in the history of CPUs pretty much, it boosts until it powers or thermal throttles, whichever comes first, it's just very very hard to cool so usually thermal throttling comes first.

 

[Journey]

I though 94°C / 95°C is their new boost temp: that is while the temp is not higher than 95°C it will boost clocks until that point. So temps don't tell you the real clocks as a poor cooler might hit 4.6GHz at 95°C, a good cooler might hit 5.0GHz at the same 95°C, while an excellent cooler might hit 5.5GHz. (All numbers plucked out of the air to give an example!)

Yes, that is pretty much how it works. You'll see some interesting results coming up, with people running them on Wraith Stealth and other low end coolers to show how the 95c boost algo works.